NRAS mutant melanoma arising in a giant congenital melanocytic nevus in an infant.

Pediatric melanomas are uncommon and sometimes arise in the background of giant congenital melanocytic nevus (GCMN). A 1-year-old girl was born with GCMN affecting her left half of the face and smaller nodules affecting trunk, hands, and feet. She developed an ulcerated lesion on the left temporoparietal scalp. The lesion showed features of GCMN along with large nests of a tumor composed of round cells with a vesicular nucleus, prominent nucleolus, plentiful mitoses, and areas of necrosis. Immunostaining for desmin, LCA, CD 20, CD 34, CD 99, BCL-2, and FLI1 was negative. Tumor cells showed immunopositivity for S-100 and HMB-45 confirming the diagnosis of melanoma. Immunostaining for BRAF V600E was negative; however, NRAS mutation was detected on next-generation sequencing. Unlike adult melanomas BRAF mutations are rare but NRAS mutations have been reported in pediatric melanomas. Adjunctive molecular testing will be important to understand the genetic basis of this disease and future targeted therapy.

Squash cytology of a case of medulloblastoma with myogenic differentiation.

Medulloblastoma with myogenic differentiation is not a distinct entity but a pattern of differentiation seen in <1% of medulloblastomas. Although squash cytology of medulloblastoma is well described, there are no reports available describing squash cytomorphology of this unusual variant of medulloblastoma. Intraoperative squash smears on a 2-year-old girl with a midline posterior fossa space occupying lesion revealed features of an embryonal tumor composed of small, round, and blue cells. In addition, it had several large, round, eosinophilic rhabomyoblasts, and a few strap cells scattered among the sea of small blue cells. Subsequent histology showed features of a medulloblastoma, classic type with myogenic differentiation. Molecular subtyping, based on immunohistochemistry alone, was in keeping with a non-Wnt/non-SHH activated type. Here we describe the squash cytomorphological details of a case of medulloblastoma with myogenic differentiation, along with its cytological differentials.

Diagnostic and prognostic utility of SF1, IGF2 and p57 immunoexpression in pediatric adrenal cortical tumors.

BACKGROUND: Adrenocortical tumors (ACT) are uncommon in the pediatric age group. Using the standard Weiss criteria in pediatric tumors leads to overdiagnosis. This has led to the development of newer systems such as Weineke criteria. Ki67 labeling index aids in differentiating adenomas from carcinomas. We aim to evaluate the diagnostic and prognostic role of Ki67 labeling index, along with immunoexpression of steroidogenic factor-1, insulin like growth factor 2 and p57, in pediatric ACTs diagnosed using Weineke criteria. METHODS: We have studied 25 cases of pediatric ACTs. Immunohistochemical staining for Ki67, SF-1, IGF2 and p57 was done in all cases and the result was correlated with the morphological diagnosis using the Weineke criteria. RESULTS: Ki67 labeling index showed complete concordance with the morphological diagnosis. SF-1 and IGF2 showed similar correlation with the diagnosis, with IGF-2 proving to be a more specific marker. Increased Ki67, SF-1 and IGF2 immunostaining also correlated with worse survival. p57 was more specific in determining benign status of a tumor. CONCLUSION: SF-1 and IGF2 are highly sensitive markers of malignancy in pediatric ACTs and can be used in combination with Ki67 expression for optimal diagnostic and prognostic assessment of pediatric ACTs. TYPE OF STUDY: Prognosis study. LEVEL OF EVIDENCE: Level II.

Cytological diagnosis of mesoblastic nephroma: A report of three cases with summary of prior published cases.

Congenital mesoblastic nephroma (CMN) is a rare pediatric renal neoplasm, occurring most commonly in the first few months of life, with a favourable clinical outcome. Accurate pre-operative cytological diagnosis of this entity is important as pre-operative chemotherapy is not recommended and surgery is the treatment of choice. Cytodiagnosis of this rare tumor is discussed in only a few case reports. Here two cases of CMN and one case of cellular congenital mesoblastic nephroma (CCMN) diagnosed on FNAC along with their morphological differential diagnoses has been reported. They also take this opportunity to compare the cytological features of CMN with cellular CMN. Diagn. Cytopathol. 2016;44:823-827. © 2016 Wiley Periodicals, Inc.

High-grade plasmablastic neoplasm of humerus in an HIV-negative patient, which was indeterminate between plasmablastic lymphoma and plasmablastic myeloma.

Plasmablastic lymphoma (PBL) of bone is a rare neoplasm that shares many confusing cytomorphological and immunohistochemical features with plasmablastic plasma cell myeloma (PBPCM). A 47-year-old female patient presented with a bony swelling and bone pain in the left humerus for the last 6 months. On radiological examination (x-ray and computed tomography) it appeared to be a lytic lesion, and a pathological fracture was detected. The patient was HIV-negative. Fine needle aspiration (FNA) was done from the lesion, which was inconclusive. Subsequently, incisional biopsy was taken. Histopathological examination and immunohistochemistry confirmed a high-grade plasmablastic neoplasm, favoring a diagnosis of PBL. Most of the reported cases of PBL have occurred in HIV-positive patients, and the bone is a very rare site. PBL can be confused with PBPCM. A final diagnosis should be rendered only after thorough histopathological and immunohistochemical examination.

Neurofibroma of kidney: an uncommon neoplasm and diagnostic dilemma with solitary fibrous tumor.

Neurofibroma of kidney is an extremely rare tumor. To our knowledge, only five such cases have been reported worldwide till date. Here, we report a solitary neurofibroma of right kidney in a 54-year-old woman. Radiological investigations (ultrasonography and computed tomography) detected a solid mass in the upper pole of right kidney and clinicoradiologically renal cell carcinoma was suspected. A radical nephrectomy was performed under diagnosis of cancer. Microscopically, tumor consisted of benign spindle-shaped cells accompanied by fibrous tissue. Differential diagnoses of neurofibroma and solitary fibrous tumor (SFT) were made on morphological features. Immunohistochemically, the tumor cells were positive for S-100 protein, but negative for CD34 and CD99. Thus, a diagnosis of neurofibroma was established.

Role of cytology in diagnosis of soft tissue sarcomas with special reference to false positive cases.

BACKGROUND: Histological diagnosis of soft tissue sarcomas is a difficult job not only for diverse architecture of different variants but also for variability in picture among different parts of a single tumor. Thus, cytodiagnosis of these tumors is one of the most challenging jobs. AIMS: To evaluate the role of fine needle aspiration cytology in diagnosis of soft tissue malignancies and discuss the false-positive cases with particular reference to causes of misdiagnosis and possible ways of correction. MATERIALS AND METHODS: In the present study, we used cytology for categorization of 59 soft tissue malignancies according to predominant cell type and also on the basis of differentiation. RESULTS: Out of 59 cytodiagnosed malignant soft tissue tumors, 36 were classified as high grade and rest as low grade. Spindle cell sarcoma was the commonest diagnosis, followed by pleomorphic variant. Histological correlations were performed in 47 cases showing consistency in 41 cases. Rest six cases with disparity were further discussed to ascertain causes of failures and to chalk out possible plans to evade these pitfalls in future. CONCLUSIONS: Overall our study established the role of cytology in diagnosis of soft tissue sarcomas with good cytohistological correlation rate (87.2%).

Fine needle aspiration cytology of parapharyngeal tumors.

BACKGROUND: Parapharyngeal tumors are rare and often pose diagnostic difficulties due to their location and plethora of presentations. OBJECTIVES: The study was undertaken to study the occurrence in the population and to evaluate the exact nature by fine needle aspiration cytology (FNAC). MATERIALS AND METHODS: A total of five hundred and six cases of lateral neck lesions were studied over three and half years. Of these 56 suspected parapharyngeal masses were selected by clinical and radiological methods. Cytopathology evaluation was done by fine needle aspiration cytology with computed tomography and ultrasonography guidance wherever necessary. Histopathology confirmation was available in all the cases. RESULTS: On FNAC diagnosis could be established in 54 cases while in two cases the material was insufficient to establish a diagnosis. The tumors encountered were, pleomorphic adenoma (33), schwannoma (3), neurofibroma (11), paraganglioma (5), angiofibroma (1) and adenoid cystic carcinoma (1). Four false positives and two false negative cases were encountered. Overall sensitivity was 96%, with specificity of 99% and accuracy being 98.8%. CONCLUSIONS: With proper clinical and radiological assessment, FNAC can be extremely useful in diagnosing most of these lesions except a few which need histopathological and even immunohistochemical confirmation.

Gaucher's disease with uncommon presentations.

Gaucher's disease is the most common lysosomal storage disorder gene defect, which leads to deficiency or decreased activity of glucocerebrosidase, followed by accumulation of glucosylceramide. There is autosomal recessive transmission leading to varied clinical manifestations. This disease has three main types: Type I - nonneuronopathic; type II - acute neuronopathic; and type III - chronic neuronopathic. The nonneuronopathic type has the highest prevalence and also the greatest variability. The authors here report two cases of Gaucher's disease with uncommon presentations in early childhood, highlighting the importance of early diagnosis of the disease, as now-a-days enzyme replacement therapy may arrest further progress of disease.

Extranodal non-Hodgkin's lymphoma presenting as an ovarian mass.

An 8-year-old female presented with an abdominal lump. A ultrasonography showed a heterogeneous, mainly solid space-occupying lesion with few cystic components and irregular margin in both adnexae measuring 10.5 x 5.2 x 3.5 cm and 9.2 x 4.8 x 3.0 cm. The tumors were removed by exploratory laparotomy and the histopathological report was primary NHL of the ovary. The uterus and cervix were healthy and there was no tumor extension or omental deposit. The patient was referred for chemotherapy.

Cytodiagnosis of filarial infections from an endemic area.

OBJECTIVE: To throw light on cytologic findings as a possible mode of diagnosis of lymphatic filariasis. STUDY DESIGN: Filariasis has worldwide distribution, but lymphatic filariasis predominantly affects tropical and subtropical regions. Demonstration of microfilaremia, the specific test for diagnosis of lymphatic filariasis, often shows false negative results in endemic areas. The present study, done in an endemic area, showed the presence of microfilariae or adult worms of Wuchereria bancrofti in fine needle aspirates collected from amicrofilariaemic cases. In a few cases the discovery was incidental. A total 4,534 cases undergoing cytologic evaluation were carefully screened for the presence of adult worms or larvae, irrespective of clinical diagnosis. Microfilariae were demonstrated in both clinically suspected cases of filariasis and asymptomatic cases. RESULTS: A total of 1 positive cases were found; in 4 cases the clinical diagnosis was lymphatic filariasis, and 7 cases were asymptomatic. All 11 cases were amicrofilariaemic. CONCLUSION: Various sophisticated investigations are used for diagnosis of lymphatic filariasis without microfilaremia. Fine needle aspiration cytology, being a cheap, simple and easy procedure, may have some role in this field, but further detailed studies are needed before any final claim.

Recurrent and aggressive chondroblastoma: a case report.

Recurrent chondroblastoma with pulmonary and palatal metastasis is a rare occurrence. We report the cytological and histological findings of such a case in a 33 years old male, where the primary diagnosis of metastatic chondroblastoma was made on FNAC, which was later confirmed on histopathology. The present case highlights that, some chondroblastomas do exist, that are capable of pursuing a malignant course.