Thyroid poorly differentiated carcinoma metastatic to pancreas diagnosed by fine-needle aspiration and demonstrating a novel BRAF fusion.

Differentiating pancreatic duct adenocarcinoma from metastasis can be challenging by morphology alone. Metastasis from a classic papillary thyroid carcinoma can present as a poorly differentiated carcinoma and mimic pancreatic ductal adenocarcinoma's morphology.

Fungal Otitis Externa (Otomycosis) Associated with Aspergillus Flavus: A Case Image.

A 48-year-old man presented with a chief complaint of intermittent right ear otorrhea of several-month duration, occasional otalgia and progressive unilateral hearing impairment. He also reported frequent episodes of headache and pressure in the sinuses and maxilla. Previous systemic treatment with antibiotics failed to alleviate the symptoms. A head/neck CT showed completely normal mastoid, middle ear and external auditory canal regions without any evidence of opacification or bone erosion. Otoscopic examination of the right ear disclosed aggregates of dried, brown, fibrillar material and debris occluding the external auditory canal and obstructing the otherwise intact tympanic membrane. Dilation of the external auditory canal or thickening of the tympanic membrane were not appreciated. The canal was debrided and the fibrillar material was placed in formalin. Histopathologic examination revealed numerous branching, septated fungal hyphae organized in densely-packed clusters. In other areas, the fungal hyphae abutted or were attached to lamellated collections of orthokeratin. As highlighted by GMS staining, the fungi were morphologically compatible with Aspergillus species. The clinicopathologic findings supported a diagnosis of fungal otitis externa, while the numerous anucleate squamous cells were compatible with colonization of an underlying, probably developing, cholesteatoma. Culture of material isolated from the external auditory canal confirmed the presence of Aspergillus flavus. In this illustrative case, we present the main clinical and microscopic characteristics of Aspergillus-related otomycosis developing in the setting of a tautochronous cholesteatoma.

SMARCB1-Deficient Skull Base Chondrosarcoma with 12p Duplication Presenting as Somatic-Type Malignancy Arising from Metastatic Seminoma.

Somatic-type malignancy (STM) can occur infrequently within a primary or metastatic testicular germ cell tumor (TGCT) and is associated with dismal prognosis and survival. STM with chondrosarcomatous features is exceedingly rare and head and neck involvement has not been previously documented. A 39-year-old white man presented with nasal obstruction and epistaxis. Imaging disclosed a 6.9-cm expansile tumor involving the nasal cavity and skull base with intraorbital and intracranial extension. The histopathologic properties of the tumor were compatible with chondrosarcoma, grade II-III. Immunohistochemically, malignant cells were strongly and diffusely positive for S100 and epithelial markers, and showed loss of SMARCB1 expression. IDH1/2 mutations were not detected. Following whole-body PET scan, a 7.0-cm left testicular mass was discovered and diagnosed as seminoma with syncytiotrophoblastic cells, stage pT3NXM1b. Extensive retroperitoneal, mediastinal, and supraclavicular lymphadenopathy was also noticed. Histopathologic examination of the left supraclavicular lymph node revealed metastatic seminoma. By FISH, most metastatic nodal seminoma cells harbored 1 to 4 copies of isochromosome 12p, while the chondrosarcoma featured duplication of 12p. Presence of a malignant TGCT with disseminated supradiaphragmatic lymphadenopathy, the unique immunophenotypic properties of the skull-based chondrosarcoma and lack of IDH1/2 aberrations with gain of 12p strongly support the diagnosis of STM chondrosarcoma arising from metastatic TGCT. The patient did not respond to chemotherapy and succumbed three months after diagnosis. Although exceedingly uncommon, metastasis to the head and neck may occur in patients with TGCT. This case of STM chondrosarcoma demonstrated divergent immunophenotypic and molecular characteristics compared to "typical" examples of head and neck chondrosarcoma. High index of suspicion is advised regarding the diagnosis of lesions that present with otherwise typical histomorphology but unexpected immunohistochemical or molecular features.

Cytopathology of mesenchymal tumors of the thyroid gland: analysis of 12 cases from multinational institutions with review of the literature.

INTRODUCTION: Mesenchymal tumors of the thyroid gland are extremely rare. We report the cytomorphologic characteristics of 12 mesenchymal tumors occurring in the thyroid gland and highlight the diagnostic difficulties encountered in their cytologic evaluation. MATERIALS AND METHODS: The cytopathology and surgical pathology archives from 5 large institutions were searched for thyroid mesenchymal tumors that had an FNA available for review. Clinicopathologic and cytomorphologic characteristics for each case were evaluated. RESULTS: Twelve cases of mesenchymal tumors occurring in the thyroid were identified in our search. Patient age ranged from 28 to 84 years (median, 60 years). The cases occurred in 7 women and 5 men. The tumor size ranged from 1.4 to 14 cm (median, 3.3 cm). The tumors were as follows: hemangioma (n = 4; 33.3%), angiosarcoma (n = 2; 16.7%), schwannoma (n = 2; 16.7%), solitary fibrous tumor (n = 2, 16.7%), metastatic synovial sarcoma (n = 1, 8.3%) and metastatic pleomorphic rhabdomyosarcoma (n = 1, 8.3%). The cytomorphologic features of the tumors were similar to those of their counterparts occurring in different sites. An accurate diagnosis was achieved in six primary thyroid mesenchymal cases (60%). Five patients (41.7%) underwent total thyroidectomy, and 3 patients received partial thyroidectomy (25%). Three patients (25%) did not receive a thyroidectomy and subsequent surgical information was not available in 1 case (8.3%). CONCLUSIONS: Mesenchymal tumors of the thyroid are extremely uncommon. Cytologic diagnosis of these tumors is often challenging due to the morphologic overlap with diverse epithelial and non-epithelial thyroid lesions. Ancillary studies such as immunohistochemistry and molecular studies are essential for accurate diagnosis.

Signet-ring cell sinus histiocytosis: report of the clinicopathologic characteristics of 4 cases with emphasis on the differential diagnosis of signet-ring cell lesions.

Signet-ring cell sinus histiocytosis (SRCSH) represents a distinctly rare reactive phenomenon predominantly affecting axillary and pelvic lymph nodes (LNs) of individuals with breast or prostatic adenocarcinoma. Reports of SRCSH in the literature are sparse with only 12 previous examples, thus underscoring the rarity of this process. Here, we report 4 additional SRCSH cases affecting 2 women and 2 men (M/F = 1:1; age range: 50-71 years; mean age = 61 years). In the 2 men, pelvic LNs were excised during radical cystoprostatectomy for genitourinary cancer, whereas in one woman, SRCSH was incidentally discovered in axillary LNs during mastectomy for breast adenocarcinoma. The other female patient presented with a history of aortic valve replacement and enlarged supraclavicular LNs. Microscopically, all involved LNs exhibited marked distention with filling of the subcapsular and medullary sinuses by sheets of signet-ring histiocytes containing a singular large, cytoplasmic vacuole and a crescentic nucleus. Overt cytologic atypia, pleomorphism, and mitoses were absent. Erythrophagocytosis and occasional fibrosis were appreciated. None of the LNs with SRCSH showed evidence of metastatic tumor. Immunohistochemically, signet-ring sinus histiocytes were invariably positive for CD68 and CD163 but were negative for pancytokeratins. The histopathologic characteristics of SRCSH, albeit bland, in conjunction with the patient's medical history, may be misinterpreted as metastatic adenocarcinoma with signet-ring cell configuration. Immunohistochemical confirmation of the histiocytic lineage of the lesional cells in SRCSH usually suffices for rendering an accurate diagnosis. The underlying pathogenetic mechanism and possible biologic significance of SRCSH remain currently unknown.

Sarcoma with MGA::NUTM1 fusion: a report of three cases and literature review.

AIMS: NUTM1-rearranged sarcoma is an emerging entity that differs from NUT carcinoma at the molecular level, with most of the former tumours harbouring fusions involving genes in the MYC-associated factor X dimerization (MAD) transcription family (MXD1, MXD4, MXI1 [or MXD2], and MGA). MGA::NUTM1 is one of the most recently described novel gene fusions associated with NUTM1-rearranged sarcoma. Herein we describe the clinicopathologic features of three sarcomas with an MGA::NUTM1 fusion. METHODS AND RESULTS: The three study patients were male, with an age range of 10-28 years. The tumour sites were deep soft tissue of the thigh, the chest wall, and the pelvis. All three tumours were aggressive, with multiple recurrences and metastases. Histologically, the tumours were composed of monotonous spindle, round, or epithelioid cells in variably hyalinized stroma and prominent aggregates of amianthoid fibre-like collagen or collagen rosettes. Mitotic activity was relatively low (5-12 mitotic figures per 10 hhpf). All tumours tested expressed NUT, with one tumour having S100 protein expression and two tumours having CD99 and CD56 expression. The genetic breakpoints were MGA exon 21, MGA exon 22, and NUTM1 exon 3. CONCLUSION: MGA::NUTM1 sarcoma often exhibits hyalinized stroma with amianthoid fibre-like collagen or collagen rosettes in the presence of monotonous round, epithelioid, or spindle cell morphology. NUT immunohistochemistry and molecular testing can help confirm the diagnosis.

Cytopathology of benign sebaceous salivary gland neoplasia: Comparison of two analogous yet dissimilar entities.

INTRODUCTION: Benign sebaceous salivary gland (SG) neoplasms represent approximately 0.2% of all salivary gland neoplasms. Not only are fine needle aspiration (FNA) biopsy findings of sebaceous adenoma (SA) and sebaceous lymphadenoma (SLA) limited, but their findings are also rarely compared with one another. MATERIALS AND METHODS: Our cytopathology files were searched for examples of benign sebaceous SG neoplasms with concomitant histopathological verification. FNA biopsy and cell collection were performed using standard technique. RESULTS: One case each of parotid SA and parotid SLA showed markedly dissimilar cytomorphology. The SA case was composed of a repetitive population of profusely multivacuolated polygonal cells with single and multiple nuclei, and was specifically recognised cytologically as a sebaceous neoplasm due to its characteristic cytoplasmic vacuolisation. The SLA case, however, was characterised by smears filled primarily with lymphocytes and only scant widely scattered basaloid cell clusters. A non-specific diagnosis of basaloid neoplasm was rendered. In retrospect, recognition of sebaceous differentiation was limited to rare cell groups. CONCLUSION: Though nominally, epidemiologically, and to a degree histopathologically analogous, the cytopathology of SA and SLA are markedly dissimilar, reflecting the dominant cell component in each. With FNA biopsy, a specific interpretation is more likely for SA than SLA due to the overwhelming obscuring lymphoid population in the latter.

Low-grade Hidradenocarcinomas: A Clinicopathologic Study of an Unusual Carcinoma That Can Mimic its Benign Counterpart.

Hidradenocarcinomas are rare cutaneous adnexal malignancies with sweat gland differentiation that can show a broad spectrum of histomorphologic appearances, ranging from low to high grade. The diagnosis of low-grade hidradenocarcinoma can be challenging and may be mistaken for benign hidradenomas, especially on superficial and partial samples. We performed a retrospective analysis of 16 low-grade hidradenocarcinomas, obtained from 4 large academic institutions. All neoplasms presented clinically as nodular lesions that ranged in size from 1.5 to 6.0 cm. All patients were adults and their age ranged from 33 to 74 years of age. All cases shared features similar to hidradenomas in the surface and mid portion of the tumors and all tumors had 1 or more histomorphologic clues to malignancy, including the presence of an asymmetric and infiltrative growth pattern (especially at the base of the tumors), perineurial invasion, and a desmoplastic stromal reaction. In the tumors evaluated for immunohistochemistry, the tumor cells were positive for p63, EMA, AE1/AE3, MNF116, and CK7. Three patients underwent sentinel lymph node biopsy, and 2 cases showed metastatic disease to regional lymph nodes. All cases (including the 2 cases that had regional lymph node metastasis), showed no local recurrence or distant metastasis observed after a complete re-excision of the tumors (follow-up range from 6 to 72 mo). Our study highlights the salient clinical and histopathologic features of low-grade hidradenocarcinomas and emphasizes the potential diagnostic pitfalls in distinguishing this entity from other neoplasms. Our results indicate that a combination of thorough histopathologic inspection is necessary to support the diagnosis of this rare neoplasm. These tumors can be exceedingly difficult to diagnose and awareness of the subtle features of low-grade hidradenocarcinoma is of importance are as it remains a diagnostic challenge for practicing pathologists.

Cytopathology of salivary gland myoepithelial carcinoma: A study of 13 cases and review of the literature.

INTRODUCTION: Myoepithelial carcinoma (MECA) is an infrequently recognized salivary gland (SG) neoplasm that commonly develops within a preexisting pleomorphic adenoma (MECA ex PA). Fine-needle aspiration (FNA) biopsy reports of this neoplasm are largely restricted to small series and single case reports. METHODS: Our cytopathology files were searched for examples of SG MECA/MECA ex PA having confirmatory histopathologic verification. Conventional FNA biopsy smears were performed, and exfoliative specimens processed using standard techniques. RESULTS: Thirteen cases from 9 patients (M:F = 3.5:1; age range: 36 to 95 years, mean age = 60 years) met inclusion criteria. FNA biopsy sites included parotid gland (4), trunk (2), scalp (2), and neck (2). Exfoliative specimens included pleural fluid (1), bronchial brushing (1), and bronchoalveolar lavage (1). Most cases were metastatic deposits (8; 62%), 4 were primary neoplasms, and 1 a local recurrence. FNA diagnoses were MECA ex PA (6; 46%), myoepithelial neoplasm (2), PA (2), basaloid neoplasm (1), atypical myoepithelial cells (1), and myxoma (1). Ancillary testing in 2 cases showed positive staining for myoepithelial markers. Cytologic features were that of a low-grade neoplasm composed principally of epithelioid/polygonal cells exhibiting minimal if any cytologic atypia. Myxoid and chondromyxoid stroma was often the dominant feature in MECA ex PA aspirates. CONCLUSION: In the primary setting, a cytologic diagnosis of MECA/MECA ex PA is extremely challenging if at all possible. Due to overwhelming amounts of stroma, the diagnosis may be challenging in some cases of metastatic MECA ex PA.

Synovial sarcoma: cytopathology of 51 cases highlighting the application of ancillary molecular testing.

INTRODUCTION: Among sarcomas, synovial sarcoma (SS) is defined by its unique SS18 cytogenetic translocation. Fine needle aspiration (FNA) biopsy is in a key position to exploit this uniqueness for diagnostic purposes. MATERIALS AND METHODS: Our cytopathology files were searched for examples of SS with histopathologic verification. FNA biopsy, imprint smears, and core needle biopsy (CNB) were performed using standard techniques. RESULTS: Fifty-one cases from 49 patients (male/female ratio, 1:1; age range, 12-79 years; mean age, 40 years) met the inclusion criteria. Of the 51 cases, 44 (86%) were FNAs, 6 were cytology imprints, and 1 was pleural fluid. Eleven aspirates had concurrent CNB. All cases had tissue confirmation. The biopsy sites included extremities (n = 24; 47%), trunk (n = 12; 24%), lung (n = 8; 16%), head or neck (n = 6; 12%), and pleural fluid (n = 1; 2%). The aspirates were from primary (n = 36; 71%), metastatic (n = 12; 24%), and recurrent (n = 3; 5%) neoplasms. The cytologic diagnoses were SS (69%), suspicious for SS (12%), malignancy (10%), spindle cell neoplasm (4%), and malignancy other than SS (6%). In general, smears and imprints contained dense cell aggregates and single cells composed of a monotonous population having fusiform, rounded, or ovoid banal nuclei and scant cytoplasm. Poorly differentiated SS showed both large epithelioid cell and small cell cytomorphology. When performed, SS18 immunohistochemical and genetic testing was positive in all 19 FNA and 3 CNB cases. CONCLUSIONS: When coupled with appropriate ancillary testing, FNA biopsy allows for a specific, accurate diagnosis of SS in most cases.

Fine needle aspiration cytopathology of pleomorphic dermal sarcoma.

INTRODUCTION: Pleomorphic dermal sarcoma (PDS) is an uncommon cutaneous mesenchymal neoplasm. It is cytomorphologically identical to atypical fibroxanthoma (AFX), but differs due to its invasion beyond the dermis. We undertook an examination of our experience with fine needle aspiration (FNA) biopsy cytology of PDS. MATERIALS AND METHODS: Our cytopathology files were searched for examples of PDS with concomitant histopathological verification. FNA biopsy smears and cell collection were performed using standard techniques. RESULTS: Seven cases of PDS were retrieved from four different patients (M:F, 1:1; age range: 63-88 years; mean age = 78 years). All patients (57%) presented with a primary tumour with one having an FNA biopsy of two local recurrences and a single distant metastasis. Five aspirates were from the extremities and two from the head/neck. Tumours ranged from 1.0 to 3.5 cm (mean, 2.2 cm). Specific cytological diagnoses were pleomorphic spindle/epithelioid sarcoma (3 cases), PDS (2), AFX (1), and atypical myofibroblastic lesion, query nodular fasciitis (1). Immunohistochemical (IHC) staining from FNA-generated cell blocks in two cases showed non-specific staining with vimentin in both cases; positive CD10, CD68, and INI-1 staining in one case; and smooth muscle actin expression in the other. Multiple negative stains were performed in both of these cases to exclude malignant melanoma, carcinoma, and specific forms of sarcoma. Cytopathology consisted of a mixture of spindle, epithelioid, and bizarre pleomorphic cells. CONCLUSION: Coupled with ancillary IHC stains, FNA biopsy can help recognise PDS as a sarcomatous cutaneous neoplasm, but is unable to distinguish PDS from AFX.

Mycobacterial Spindle Cell Pseudotumor of the Nasal Cavity.

BACKGROUND: Mycobacterial spindle cell pseudotumor (MSCP) represents an uncommon tumor-like proliferation associated with nontuberculous mycobacterial infection, i.e., M. avium intracellulare, affecting primarily the lymph nodes of immunocompromised men in their 5th decade. Involvement of the nasal cavity by MSCP is exceedingly rare with only 3 well-documented examples in the literature. METHODS: A 74-year-old, HIV-negative, man presented with a 0.5-cm nodule of the left nasal cavity clinically presenting as a "nasal polyp." His medical history was significant for colonic adenocarcinoma, cutaneous basal cell carcinoma, and chronic lymphocytic leukemia (CLL) transforming to B-cell prolymphocytic leukemia, responsive to chemotherapy. The patient was diagnosed with prostatic adenocarcinoma treated with radiotherapy two months before the nasal lesion was detected. No lymph node enlargement, pulmonary involvement or hepatosplenomegaly were noticed. The nasal nodule was surgically excised and histopathologically examined to rule out metastatic disease or CLL relapse. RESULTS: Microscopically, the lesion comprised a well-circumscribed, monotonous, spindle cell population in a vaguely storiform arrangement mixed with a heavy infiltrate of neutrophils and sparse lymphocytes. The spindle cells featured finely granular rich eosinophilic cytoplasm with rounded, oval to epithelioid, or elongated nuclei with vesicular chromatin and one or two distinct nucleoli. The lesional cells lacked overt cytologic atypia and showed occasional regular mitoses. The surface epithelium was intact or focally ulcerated. By immunohistochemistry, the spindle cell population stained strongly and diffusely for CD68 and was negative for AE1/AE3, SMA, CD34, and PSA. CD3 highlighted scattered lymphocytes. Ziehl-Neelsen stain disclosed numerous intracytoplasmic acid-fast bacilli. A diagnosis of MSCP was rendered. No recurrences were observed during a 24-month follow-up period. CONCLUSION: Although exceptionally rare, MSCP should be considered in the differential diagnosis of nodular lesions of the nasal cavity that are characterized microscopically by marked spindle cell proliferation in a vague storiform pattern, admixed with a lymphocytic or mixed inflammatory infiltrate. A negative medical history for HIV infection and medication-induced immunosuppression should not preclude a diagnosis of MSCP, particularly in extranodal sites. Once the diagnosis is established, prognosis appears to be excellent for nasal MSCP following conservative surgical excision.

Atypical spindle cell/pleomorphic lipomatous tumour (ASPLT): A report of three FNA cases and comparison with spindle cell/pleomorphic lipoma cytopathology.

INTRODUCTION: Atypical spindle cell/pleomorphic lipomatous tumour (ASPLT) is an infrequently appreciated benign lipomatous neoplasm newly accepted into the most recent WHO classification of soft tissue tumours. MATERIALS AND METHODS: Our cytopathology files were searched for examples of ASPLT and spindle cell/pleomorphic lipoma (SCPL) having histopathological verification. Conventional fine needle aspiration (FNA) biopsy smears were performed using standard techniques. RESULTS: Eleven patients including three cases of ASPLT and eight of SCPL (M:F = 4.5:1; age range: 39-97 years, mean age = 60 years) met the inclusion criteria. FNA biopsy sites included extremity (5, 45%), trunk (3, 27%), and head/neck (3, 27%). All aspirates were from primary neoplasms. FNA diagnoses of ASPLT cases were spindle cell lipomatous neoplasm, fibrotic low-grade SC neoplasm, and myxoid lipomatous neoplasm. Eight SCPL cases were diagnosed as spindle cell neoplasm (3), spindle cell lipoma (SCL) (1), pleomorphic lipoma (1), suspicious for SCL (1), benign adipose tissue (1), and benign spindle cells and connective tissue (1). Ancillary testing in two ASPLT cases showed positive CD34 and negative MDM2 immunostain in one, and negative FISH results for MDM2 and DDIT3 in another. CONCLUSION: ASPLT is a novel lipomatous neoplasm simulating primarily SCPL and atypical lipoma/well-differentiated liposarcoma. Diligent cytomorphological observation, clinical information, and ancillary testing may allow for its specific recognition using FNA biopsy.

Adenoid Cystic Carcinoma With Striking Tubular Hypereosinophilia: A Unique Pattern Associated With Nonparotid Location and Both Canonical and Novel EWSR1::MYB and FUS::MYB Fusions.

The classification of salivary gland tumors is ever-evolving with new variants of tumors being described every year. Next-generation sequencing panels have helped to prove and disprove prior assumptions about tumors' relationships to one another, and have helped refine this classification. Adenoid cystic carcinoma (AdCC) is one of the most common salivary gland malignancies and occurs at all major and minor salivary gland and seromucous gland sites. Most AdCC are predominantly myoepithelial and basaloid with variable cribriform, tubular, and solid growth. The luminal tubular elements are often less conspicuous. AdCC has largely been characterized by canonical MYB fusions, with MYB::NFIB and rarer MYBL1::NFIB. Anecdotal cases of AdCC, mostly in nonmajor salivary gland sites, have been noted to have unusual patterns, including squamous differentiation and macrocystic growth. Recently, this has led to the recognition of a subtype termed "metatypical adenoid cystic carcinoma." Another unusual histology that we have seen with a wide range of architecture, is striking tubular hypereosinophilia. The hypereosinophilia and luminal cell prominence is in stark contrast to the vast majority of AdCC that are basaloid and myoepithelial predominant. A total of 16 cases with tubular hypereosinophilia were collected, forming morular, solid, micropapillary, and glomeruloid growth, and occasionally having rhabdoid or Paneth-like cells. They were subjected to molecular profiling demonstrating canonical MYB::NFIB (5 cases) and MYBL1::NFIB (2 cases), as well as noncanonical EWSR1::MYB (2 cases) and FUS::MYB (1 case). The remaining 6 cases had either no fusion (3 cases) or failed sequencing (3 cases). All cases were present in nonmajor salivary gland sites, with seromucous glands being the most common. These include sinonasal tract (7 cases), laryngotracheal (2 cases), external auditory canal (2 cases), nasopharynx (1 case), base of tongue (2 cases), palate (1 case), and floor of mouth (1 case). A tissue microarray of 102 conventional AdCC, including many in major salivary gland sites was examined for EWSR1 and FUS by fluorescence in situ hybridization and showed that these novel fusions were isolated to this histology and nonmajor salivary gland location. In summary, complex and striking tubular hypereosinophilia and diverse architectures are present within the spectrum of AdCC, particularly in seromucous gland sites, and may show variant EWSR1/FUS::MYB fusions.

Haemoglobin spherulosis: Fine needle aspiration biopsy of an unusual ocular lesion.

OBJECTIVE: Haemoglobin spherulosis (HS) is a rare lesion occurring post-vitreous haemorrhage that is absent from the cytopathology literature. METHODS: We present the fine needle aspiration (FNA) biopsy cytological features of a case of HS occurring in a 73-year-old woman. RESULTS: FNA smears of hemorrhagic vitreous fluid showed numerous variably sized smooth glassy spherules ranging from 3-20 µm. Occasional red cells and a rare lymphocyte were observed, but other cell types were absent. Immunohistochemical staining of a cell block showed diffuse positive staining of spherules with haemoglobin A. CONCLUSIONS: HS is a rare lesion that occurs post-subretinal haemorrhage and may be encountered by pathologists examining ocular cytological specimens.

Benign peripheral nerve tumors: Analysis of 89 FNA cases emphasizing diagnostic accuracy and their morphologic spectrum.

INTRODUCTION: Benign peripheral nerve tumors (BPNTs) are a heterogenous group of soft tissue tumors that include a variety of nerve sheath tumors, granular cell tumor (GCT), and ganglioneuroma. Only a few large studies exist on cytopathology and diagnostic accuracy using fine-needle aspiration (FNA) biopsy for this set of neoplasms. MATERIALS AND METHODS: Both surgical and cytopathology files were searched for cases of BPNT. FNA biopsy was performed using standard techniques. RESULTS: Eighty-nine cases from 88 patients (male:female = 1:1; age range: 16-85 years, mean age, 51 years) met inclusion criteria. FNA sites included extremities (58, 65%), head/neck (14, 16%), deep (9, 10%), and trunk (8, 10%). Aspirates were from primary neoplasms in all but one instance. There were 65 schwannomas, seven neurofibromas, seven perineuriomas, seven GCTs, and three ganglioneuromas/neuromas. Aspirates of schwannoma, GCT, neurofibroma (NF), and perineurioma (PN) were correctly diagnosed in 86%, 100%, 29%, and 0% of cases, respectively. Five tumors (6%) were interpreted as either a specific sarcoma or suspicious for sarcoma. Remaining aspirates were classified as spindle cell neoplasm, salivary gland neoplasm, and nondiagnostic. Cytologic features for schwannoma, NF, PN, and ganglioneuroma showed spindle cell-dominant smears arranged mainly in syncytial clusters. GCT aspirates contained a population of epithelioid cells harboring coarsely granular cytoplasm and bare nuclei. Immunohistochemical (IHC) staining in 55 (62%) cases showed S-100 expression in 95%. CONCLUSION: FNA biopsy coupled with IHC is reliable in correctly classifying schwannoma and GCT, but less so for NF. Perineurioma can be mistaken for sarcoma.

Chondroblastoma: Cytomorphologic Analysis of 10 Cases with Review of the Literature.

INTRODUCTION: Chondroblastoma (CB) is a rare, benign cartilage-producing tumor, typically affecting the epiphysis of long bones in skeletally immature individuals. There have been only limited case reports describing the cytomorphologic features of this tumor, and thus the cytopathologic diagnostic criteria are controversial. Herein, we report the cytologic findings of 10 CB cases, discuss the diagnostic criteria and critical differential diagnosis, along with a comprehensive review of the literature. METHODS: We performed a retrospective search of our cytopathology and surgical pathology databases for cases diagnosed as CB that had corresponding cytology specimens from four large medical institutions. All available cytopathology specimens were retrieved and reviewed. Clinicopathologic and radiologic data were recorded. RESULTS: Ten cases were retrieved from 8 patients aged 15-42 years (mean, 24 years), five of whom were males. Eight cases represented primary tumors while 2 cases were recurrences. Three cases occurred in the femur, two cases occurred in the humerus, while 1 case occurred in each of the glenoid, talus, and proximal phalanx of the 3rd toe. The cytologic diagnosis of CB was achieved in 7 cases. The neoplastic mononuclear cells were present in all cases and their cytologic features were similar. These cells displayed round to oval eccentric nuclei, evenly distributed chromatin, and inconspicuous nucleoli; few of which had nuclear indentations. Multinucleated giant cells were present in 9 cases (90%). Fragments of chondromyxoid matrix were present in 4 cases on cytologic preparations (40%). Cell blocks were available in 8 cases. Mononuclear and multinucleated giant cells were present in all adequate cell blocks and their cytologic features were identical to those seen in the smears. The chondroid matrix was present in only three of the adequate cell blocks (43%). CONCLUSION: We concluded that with the appropriate clinical and radiologic setting, the diagnosis of CB can be achieved on cytology if characteristic chondroblasts are present. The presence of chondromyxoid matrix is a helpful clue but is not necessary for the diagnosis. As in surgical pathology, cytologic evaluation of bone tumors should be interpreted in conjunction with clinical and radiologic findings.

Pleomorphic hyalinizing angiectatic tumor: FNA analysis of a rare entity and review of the literature.

INTRODUCTION: The fine-needle aspiration (FNA) cytopathology of pleomorphic hyalinizing angiectatic tumor (PHAT) is the subject of a very limited number of reports. We undertook a review of our FNA experience with this neoplasm. MATERIALS AND METHODS: A search was made of our files for PHAT FNA cases with histopathologic confirmation. FNA biopsy smears and cell blocks were performed and examined using standard techniques. RESULTS: Two primary cases of histologically proven PHAT [both male, ages 56 and 60 years] met study inclusion. FNA sites included buttock and foot. A misdiagnosis of sarcoma was made in each case. Ancillary immunohistochemical testing performed in 1 case suggested angiosarcoma. Cytologic smears showed only modest cellularity with a dual population of bland spindle cells and isolated large pleomorphic cells, many harboring nuclear pseudoinclusions. Smear background was clean, and mitoses absent. CONCLUSIONS: The imitative cytopathology of PHAT with a pleomorphic sarcoma remains a pitfall in FNA specimens. Awareness of this entity and its lack of hypercellularity, necrosis, and cohesive groups of atypical cells in smears should assist the cytopathologist in avoiding a misdiagnosis of malignancy.

Chordoma: analysis of 47 fine-needle aspiration biopsy, cytologic imprint, and small biopsy specimens.

INTRODUCTION: Fine-needle aspiration (FNA) and small tissue biopsy of chordoma have been reported in several small series, but no large series exists. We undertook an examination of 47 cases (with concurrent core needle biopsy in a subset) to analyze diagnostic accuracy, cytomorphology, and immunohistochemistry. MATERIALS AND METHODS: Our cytopathology files were searched for examples of chordoma with histopathologic verification. FNA biopsy smears and core needle were performed using standard techniques. RESULTS: Forty-seven cases of chordoma were retrieved from 44 patients [M:F; 1.8:1; age range 5-81 years; mean age 55 years]. Twenty-seven presented with primary, 10 with locally recurrent, and 7 with metastatic tumors. Two aspirates were from the appendicular skeleton, 2 from the trunk, 1 from neck lymph node, and 42 aspirates (89%) from axial and peri-axial skeleton and surrounding soft tissues. Four were cytologic touch imprints while the remainder were FNA biopsy specimens. Specific cytologic diagnoses were chordoma/consistent with chordoma (44 cases, 94%), suspicious for chordoma (2), and malignant neoplasm (1). Along with a single case of benign notochordal tumor misdiagnosed as chordoma, our diagnostic accuracy was 91%. Concurrent tissue biopsy was performed in 51% of cases. Immunohistochemical staining of tumor in 29 (62%) cases showed expression of brachyury in 23 of 24 (96%) instances. Cytopathology consisted of cellular smears populated by large cells possessing enormous amounts of vacuolated and non-vacuolated cytoplasm with an abundant background myxoid/chondromyxoid stroma. CONCLUSIONS: FNA and small tissue biopsy specimens show a very high degree of diagnostic accuracy in recognition of chordoma.

Childhood sarcomas: fine-needle aspiration cytopathology with an emphasis on the use of molecular studies.

INTRODUCTION: In children and adolescents, most sarcoma subtypes have a simple karyotype with a single genetic alteration; cytologic findings combined with ancillary testing can lead to a specific diagnosis. The goal of this study was to review the use of fine-needle aspiration in conjunction with immunohistochemistry and molecular studies as a part of an integrated, multidisciplinary diagnostic workup for bone and soft tissue sarcomas in this population. MATERIALS AND METHODS: We searched for cases aged ≤18 years old with a malignant bone or soft tissue tumor that had corresponding cytology specimens from 3 institutions. Clinical data, cytologic findings and diagnoses, histologic diagnoses, and ancillary testing were documented. RESULTS: Of 99 cases, 55% were male with a mean age of 12 years. Ninety-four cases (95%) had a specific histologic diagnosis, and 84 cases (85%) were primary neoplasms. Ninety-four cases (95%) had a malignant cytologic diagnosis, and 71 cases (72%) had a specific cytologic diagnosis concordant with the histologic diagnosis. Among primary tumors with a specific histologic diagnosis, a specific cytologic diagnosis was made in 63 cases (79%). After excluding osteosarcoma, 74% of the tumors (n = 50) had molecular studies. Specific genetic alterations supporting a definitive diagnosis were found in 42 cases (84%), the majority of which were demonstrated using Fluorescence In Situ Hybridization (n = 33, 79%). CONCLUSIONS: We found that fine-needle aspiration in conjunction with core needle biopsy, immunohistochemistry, and molecular studies allowed cytopathologists to accurately classify sarcomas in a pediatric age group.