The paraneurium and the tumefactive appearance of peripheral nerve neurolymphomatosis: illustrative case.

BACKGROUND: Peripheral neurolymphomatosis (NL) is an often-misdiagnosed condition characterized by lymphomatous infiltration within the peripheral nerves. Its rarity and complexity frequently result in delayed diagnosis and suboptimal patient outcomes. This study aims to elucidate the role of the paraneurium (circumneurium) in NL, emphasizing its diagnostic and therapeutic significance. OBSERVATIONS: A 72-year-old man presented with lesions on his right lower eyelid. Initial diagnostics were inconclusive until an excisional biopsy confirmed extranodal marginal zone lymphoma. Following a complete metabolic response to rituximab treatment, the patient relapsed 14 months later with progressive lymphoma and bilateral sciatic nerve involvement, as confirmed by positron emission tomography-computed tomography and magnetic resonance imaging. LESSONS: This paper underscores the critical role of the paraneurium in NL, enhancing understanding of its pathophysiology. Integrating advanced imaging techniques have proved essential in accurately identifying neurolymphomatous involvement within the paraneurium. This study paves the way for more effective management strategies in NL and similar conditions, focusing on improving patient care and outcomes.

Malignant rhabdoid tumor: Cyto-histologic correlation and immunohistochemical characterization of a rare pediatric malignancy and its differential diagnoses.

Malignant rhabdoid tumor of the kidney (MRTK) is a rare aggressive pediatric renal tumor which can be diagnosed via fine-needle aspiration (FNA) cytology and core biopsy. The diagnosis of MRTK is challenging, and requires morphologic, immunohistochemical and clinical correlation to distinguish it from other entities. The differential diagnosis includes Wilms tumor, desmoplastic small round cell tumor, rhabdomyosarcoma, synovial sarcoma, renal medullary carcinoma, and epithelioid sarcoma. Here we describe a case of MRTK diagnosed on renal cytology and core biopsy with immunohistochemistry and follow by nephrectomy with gross and morphologic findings.

Increased ERBB2 Gene Copy Numbers Reveal a Subset of Salivary Duct Carcinomas with High Densities of Tumor Infiltrating Lymphocytes and PD-L1 Expression.

Salivary duct carcinoma (SDC) commonly expresses androgen receptor (AR) and HER2, giving rise to treatment implications. SDC may also express programmed-death-ligand-1 (PD-L1), a predictive marker of response to checkpoint inhibitors. PD-L1 can be associated with genomic instability and high density of tumor infiltrating lymphocytes (TILs). Evaluation of HER2 immunohistochemistry (IHC) in SDC is not standardized, and relationships between ERBB2 copy numbers, PD-L1 expression and TILs in SDC are unknown. We evaluated 32 SDCs for HER2, AR and PD-L1 expression (IHC), ERBB2 status (FISH) and TILs (slide review). HER2 was scored with three different systems (breast, gastric, proposed salivary gland). PD-L1 was evaluated with the combined positive score. Most patients were older men, presenting at advanced clinical stage with nodal or distant metastases. During follow-up (mean 5 years, range 6 months to 21 years), 25 of the 32 patients (78%) died of SDC. We propose a HER2 IHC scoring system which accurately predicts underlying ERBB2 amplification or increased copy numbers in SDC. Most tumors had increased ERBB2 copy numbers (19/32 amplification, 6/32 aneusomy), a finding associated with higher TIL densities (p = 0.045) and PD-L1 expression (p = 0.025). Patients with TILs ≥ 40% had better prognoses (Log-Rank p = 0.013), with TILs being favorable prognosticators in univariate analysis (Hazard ratio: 0.18, p = 0.024). A subset of SDCs with increased ERBB2 copy numbers have higher TILs and PD-L1 expression. TILs ≥ 40% are associated with better prognosis.

Well-Differentiated/Dedifferentiated Liposarcoma Arising in the Upper Aerodigestive Tract: 8 Cases Mimicking Non-adipocytic Lesions.

Well-differentiated (WDL) and dedifferentiated liposarcomas (DL) of the pharynx, larynx and oral cavity are rare, often mimicking benign lipomatous neoplasms or non-lipogenic mesenchymal tumors. Cases of WDL/DL arising in the upper aerodigestive tract, exclusive of the cervical esophagus, were reviewed. Morphologic features, ancillary studies, including fluorescence in situ hybridization (FISH) studies for CPM/MDM2, and clinical data was catalogued. Eight WDL/DL (4 WDL, 4 DL); were identified in patients ranging from 32 to 77 years (median 52.5 years; 6 males, 2 females) with sites of origin including hypopharynx (5 cases), larynx (2 cases) and oral cavity (1 case). Six of the 8 cases were received for expert consultation, and the remaining 2 cases were initially misdiagnosed as benign lymphangiomatous or fibroepithelial polyps. Morphologically, 4 tumors had areas mimicking various non-lipomatous soft tissue tumors including nodular fasciitis, mammary-type myofibroblastoma, low-grade myofibroblastic sarcoma and undifferentiated pleomorphic sarcoma, 2 cases simulated benign hypopharyngeal polyps, and 1 lesion was notable for a dense lymphoplasmacytic infiltrate suggestive of hematolymphoid neoplasm or IgG4-related sclerosing disease. FISH showed amplification of CPM/MDM2 (8/8 cases). All cases (4/4) with longer than 1-year of follow-up recurred (45-118 months) with 1 tumor showing progression to DL. WDL/DL presenting in the upper aerodigestive tract are rare and diagnostically challenging. Awareness of the morphologic spectrum of WDL/DL coupled with appropriate use of MDM2 FISH is essential for accurate classification and management, as these tumors appear to have a high risk for local recurrence and eventual dedifferentiation in these anatomical locations.

First Line Androgen Deprivation Therapy vs. Chemotherapy for Patients With Androgen Receptor Positive Recurrent or Metastatic Salivary Gland Carcinoma-A Retrospective Study.

Objectives: There is a lack of effective therapy for recurrent or metastatic salivary gland carcinoma. Androgen deprivation therapy has demonstrated efficacy in cases of salivary duct carcinoma (SDC) and high-grade adenocarcinoma not otherwise specified (NOS) that express androgen receptor. Materials and Methods: We conducted a single institution retrospective cohort study examining patients treated for recurrent/metastatic SDC or high-grade adenocarcinoma NOS of the salivary gland. Survival analyses were performed to assess for efficacy of first-line androgen deprivation therapy (ADT) vs. first-line conventional cytotoxic chemotherapy. Efficacy of salvage ADT was also assessed. Results: Fifty-eight patients were reviewed. Thirty-five patients had recurrent/metastatic disease of which 28 had SDC (80%) and 7 had high-grade adenocarcinoma NOS (20%). Median overall survival for first-line ADT was 25 months compared to 25 months for first-line chemotherapy [RR 0.54 (0.23-1.28, p = 0.16)]. Patients treated with first-line ADT had a response rate of 45% (9/20) and patients treated with first-line chemotherapy had a response rate of 14% (2/14). Six patients received salvage ADT with 1 patient demonstrating complete response and 3 with stable disease as best response (clinical benefit rate 67%). Conclusion: Overall survival for first line ADT and first line cytotoxic chemotherapy was comparable but response rates to first-line ADT were higher than those with first-line chemotherapy. Salvage ADT is active in recurrent/metastatic salivary gland carcinoma.

Mesenchymal chondrosarcomas showing immunohistochemical evidence of rhabdomyoblastic differentiation: a potential diagnostic pitfall.

The diagnosis of mesenchymal chondrosarcoma, a distinctive biphasic malignant neoplasm harboring the HEY1-NCOA2 gene fusion and consisting of primitive round to spindled cells admixed with foci of relatively mature hyaline cartilage, is usually straightforward by morphologic evaluation alone. However, in the setting of a limited biopsy, specimens lacking cartilage generate a broad differential diagnosis, encompassing a variety of other primitive sarcomas, including spindle cell/sclerosing rhabdomyosarcoma. Although a small number of cases of mesenchymal chondrosarcoma with aberrant skeletal muscle marker expression have been reported, pathologists are largely unaware of this potential diagnostic pitfall. We report 6 additional cases of mesenchymal chondrosarcoma showing expression of multiple skeletal muscle markers, including one case initially misdiagnosed as "spindle cell/sclerosing rhabdomyosarcoma" on needle biopsy. Awareness of this phenomenon and judicious application of molecular diagnostic testing for the HEY1-NCOA2 fusion are critical to avoid misclassification of mesenchymal chondrosarcoma as rhabdomyosarcoma, with potentially adverse patient impact.

Comprehensive Genomic Profiling of Central Giant Cell Lesions Identifies Clinically Relevant Genomic Alterations.

PURPOSE: Comprehensive genomic profiling (CGP) can simultaneously detect clinically relevant genomic alterations (CRGAs) in hundreds of cancer-related genes and direct treatment toward patient-specific therapy options for many tumors. This pilot study aimed to use CGP to describe CRGAs present in central giant cell lesions (CGCLs) to characterize any possible underlying genomic drivers of CGCLs. MATERIALS AND METHODS: With institutional review board approval, electronic medical records were searched for patients with histologically confirmed CGCLs who underwent biopsy at Mayo Clinic from 2000 through 2014. Clinical characteristics were recorded from the medical records. At least 50 ng of DNA was extracted from formalin-fixed paraffin-embedded archival CGCL specimens by use of hybridization-capture, adaptor ligation-based libraries targeting all exons from 315 cancer-related genes plus select introns from 28 genes commonly rearranged in cancer. Samples were sequenced to high, uniform coverage and assessed for all 4 classes of genomic alterations: base substitutions, small insertions and deletions, rearrangements, and copy number alterations. RESULTS: Of 8 CGCL specimens, 3 (37.5%) harbored CRGAs, including base substitutions in BRAF, GNAS, and KRAS that are predicted to be oncogenic. In 1 sample, focal high-level amplification of the MITF gene was detected. Rearrangement in the PDGFRB gene was identified in a fourth sample, although the significance of this alteration is uncertain. CONCLUSIONS: This pilot study shows that a relatively high frequency of CRGAs (37.5%) can be identified in CGCLs by use of CGP. Furthermore, 25% of CGCLs analyzed had somatic mutations predicted to activate the mitogen-activated protein kinase signaling pathway, suggesting it may be a driver of the aggressive behavior of these lesions. On the basis of this study, genomic profiling of a larger cohort of CGCLs to validate these observations, as well as correlate mutations with aggressive versus nonaggressive biological behavior and therapeutic responses, appears warranted.

Fusion gene profile of biphenotypic sinonasal sarcoma: an analysis of 44 cases.

AIMS: Biphenotypic sinonasal sarcoma (SNS) is a locally aggressive tumour that occurs in the sinonasal region. PAX3-MAML3 has recently been identified as a recurrent fusion gene event in this entity; however, a subset of tumours harbour alternative PAX3 rearrangement without the involvement of MAML3. In this study we sought to characterize the molecular profile of a large series of cases, with a special emphasis on tumours with alternative fusions. METHODS AND RESULTS: Forty-four examples of SNS were screened by fluorescence in-situ hybridization and reverse transcription polymerase chain reaction to better characterize its molecular profile and identify potential novel fusion genes. Twenty-four were positive for PAX3-MAML3 (55%), 15 showed rearrangements of PAX3 without MAML3 involvement (34%), one showed rearrangement of MAML3 without PAX3 involvement, and four were negative for the involvement of either gene (9%). Among 15 cases with PAX3 involvement only, three were found to harbour PAX3-FOXO1. Two of these cases arose in the nasal cavities of female patients (aged 31 and 47 years), and one showed bilateral involvement of the nasal cavities of a 35-year-old male. A fourth case involved the skull base of a 47-year-old male, and was positive for PAX3-NCOA1. Patients with fusion-negative tumours were slightly older. CONCLUSION: More than half of the SNSs in this series were positive for PAX3-MAML3. However, a subset of tumours may harbour alternative PAX3 fusion genes or show no involvement of PAX3. Except for a possible weak association between age and molecular profile, the overall morphological and immunophenotypic features of all cases seem to be similar. Because of the rarity of these tumours, the impact of the molecular profile on the clinical course of these tumours remains to be determined.

Intramuscular dirofilariasis mimicking an orbital metastasis in a patient with breast cancer.

We present the unusual case of a 74 year-old female with a history of breast cancer who presented with acute painless orbital swelling and vertical diplopia. MRI revealed a focal enhancing mass within the superior rectus muscle. As the concern for metastatic disease was high, surgical biopsy was performed and revealed an unusual mimicker of metastatic disease, the parasitic infection dirofilariasis.

Prognostic features, human papillomavirus status, and epidermal growth factor receptor expression in oral squamous cell carcinoma in young adults.

PURPOSE: There is still debate in literature about the survival outcomes of patients who have cancer of the oral cavity when young. Hence the aims were (1) to estimate disease-free survival, overall survival, and cause-specific survival in patients who developed oral cavity squamous cell carcinoma between 18 and 40 years of age and (2) to assess the clinicopathologic factors including detection of human papillomavirus and epidermal growth factor receptor (EGFR) overexpression in primary lesions affecting recurrence. METHODS: This is a retrospective case-note review and reevaluation of histopathologic slides of patients treated more than 25 years. Descriptive statistics, Cox proportional hazard models, and Kaplan-Meier survival curves were used for statistical analysis. RESULTS: A total of 62 patients were treated, with mean follow-up of 11.4 years. Forty-five were oral tongue tumors and 43 had stage I or II disease. The 5-year disease-free survival was 73.5%. The 10-year overall survival and cause-specific survival rates were 81.8% and 83.4%, respectively. Smoking and alcohol intake were not seen as risk factors in this population. Multivariate modeling identified only nodal involvement as significantly associated with overall survival and only extracapsular spread as significantly associated with locoregional recurrence. At 5 years after treatment, the cause-specific survival was 100% for patients with low EGFR expression and 81.1% for patients with high EGFR expression (hazard ratio for high vs low, 3.1; 95% confidence interval, 0.4-406.9; P = .46). Human papillomavirus was not detected in all but 2 tumor specimens. CONCLUSIONS: Survival outcomes are quite good in young patients with oral cancer.

Low-grade sinonasal sarcoma with neural and myogenic features: a clinicopathologic analysis of 28 cases.

Sarcomas of the sinonasal region are rare. We describe a distinct spindle cell sarcoma of the sinonasal region characterized by concomitant neural and myogenic differentiation. Consultation files and surgical cases from Mayo Clinic were reviewed. Twenty-eight cases were identified that met the inclusion criteria. Clinical data were collected from medical records, consultation letters, and referring pathologists. Reverse transcriptase-polymerase chain reaction for synovial sarcoma fusion transcripts was performed on 18 cases. Cytogenetic studies were performed on 2 cases. The 21 female and 7 male patients ranged in age from 24 to 85 years (mean, 52 y). All cases showed a characteristic histology, which included a cellular spindle cell neoplasm with uniform, elongate nuclei and an infiltrative growth pattern. All tumors demonstrated expression of S-100 with actin positivity in 96% of cases tested. Reverse transcriptase-polymerase chain reaction for synovial sarcoma fusion transcripts was negative in all cases tested. Cytogenetic studies conducted on 2 cases demonstrated the chromosomal translocation t(2;4). The nasal cavity (54%) and ethmoid sinus (57%) were the most commonly involved areas, singly or in combination. Follow-up information was available for 57% (16/28) of cases, with a mean of 8.3 years. Of these, 44% (7/16) experienced at least 1 recurrence. No patient has developed metastases or died of disease. We describe a unique tumor with a characteristic morphologic, immunophenotypic, and cytogenetic profile. On the basis of the locally aggressive nature of this lesion we believe it is best considered a low-grade sarcoma and suggest the term low-grade sinonasal sarcoma with neural and myogenic features.

Detection of human papilloma virus and p16 expression in high-grade adenoid cystic carcinoma of the head and neck.

Squamous cell carcinoma of the head and neck, particularly basaloid squamous cell carcinoma, may be difficult to distinguish from high-grade adenoid cystic carcinoma. Evidence of human papilloma virus (HPV) infection, particularly HPV 16, is frequently found in non-keratinizing oropharyngeal squamous cell carcinoma. Immunoreactivity for p16, a surrogate marker for HPV infection, often parallels the HPV infection status in oropharyngeal squamous cell carcinoma. However, the incidence and correlation between p16 expression and HPV infection in high-grade adenoid cystic carcinoma is unknown. Sixteen cases of high-grade adenoid cystic carcinoma, three cases of dedifferentiated adenoid cystic carcinoma and eight cases of low-/intermediate-grade adenoid cystic carcinoma were identified for inclusion in the study. All cases were tested by immunohistochemistry for p16 expression and in situ hybridization for high- and low-risk HPV. Eight cases (100%) of low-to-intermediate-grade adenoid cystic carcinoma were focally positive for p16, all of which were negative for HPV. In all, 14 of 16 cases (88%) of high-grade adenoid cystic carcinoma and three cases (100%) of dedifferentiated adenoid cystic carcinoma were positive for p16; strong and diffuse staining was noted in three cases (3 of 19, 16%). Two cases (11%) of high-grade adenoid cystic carcinoma, which were also diffusely positive for p16, showed the presence of high-risk HPV. These findings suggest that the presence of HPV infection in high-grade adenoid cystic carcinoma is infrequent, even in the presence of p16 immunostaining. Nevertheless, HPV positivity should not be used to exclude the possibility of high-grade adenoid cystic carcinoma when the differential diagnosis includes squamous cell carcinoma. Moreover, although p16 overexpression is often used as a surrogate marker for HPV in squamous cell carcinoma, it cannot be used in this manner in high-grade adenoid cystic carcinoma.

Veno-occlusive disease of the liver after blood and marrow transplantation: analysis of pre- and post-transplant risk factors associated with severity and results of therapy with tissue plasminogen activator.

We reviewed our blood and marrow transplantation (BMT) database from April 1982 to July 1996 and identified 111 of 474 patients with serum bilirubin concentration (SBR) > or = 34 micromol/l for two consecutive days within the first 20 days after related allogeneic or autologous BMT. Of the 111, 73 fulfilled the Seattle criteria for veno-occlusive disease of the liver (VOD) and had no other obvious cause for liver dysfunction. The patients were 16-60 years old (median, 39 years), and 41 were male (56%). Fourteen patients (19%) had autologous BMT, and 59 (81%) had allogeneic BMT. Twenty-eight (38%), 12 (16%), and 33 (45%) patients had severe, moderate, and mild VOD, respectively, by Seattle criteria. None of 23 patients with maximum (max) SBR > or = 257 micromol/l survived, all patients with max SBR < or = 128 micromol/l survived, and 7 of 15 patients (47%) with max SBR 128-257 micromol/l survived. The only pre-transplantation risk factor predictive of severe VOD was advanced disease state (P = 0.035), and the only transplant factors that predicted severe VOD were max SBR (P = 0.01) and maximum blood urea level (P = 0.03). Ten patients (all with creatinine levels > or = 150 micromol/l) were treated with tissue plasminogen activator; only two had a significant response and only one survived beyond day 120.