SMARCB1 deficient sinonasal carcinoma: An emerging entity with a diagnostic challenge

SMARCB1 deficient sinonasal carcinomas are rare neoplasms, classified under sinonasal undifferentiated carcinomas by the fourth edition of the World Health Organization (WHO) classification of head and neck tumors. It is characterized immunohistochemically by loss of SMARCB1(INI1) expression. We are reporting the case of a 63-year-old man who was evaluated for nasal stuffiness of 3 months duration in another hospital where a radiological evaluation showed a polypoidal soft tissue lesion in the right maxillary sinus extending to the right nasal cavity and spheno-ethmoidal sinus. He underwent excision biopsy which was reported as non- keratinizing nasopharyngeal carcinoma. He was referred to our center with residual disease in spheno-ethmoidal recess for which radiotherapy was given. After completion of radiotherapy, the primary site had no residual disease, but while on follow-up he developed left sided neck nodes within 4 months of completion of treatment. Excision of the lesion was done and histopathological and immunohistochemical analysis revealed it to be metastasis from SMARCB1 deficient sinonasal carcinoma and not nasopharyngeal carcinoma as diagnosed from the other center. This case is being reported to highlight the diagnostic challenge associated with this rare entity.

Comparison between Fluorescence in-situ Hybridization (FISH), Reverse Transcriptase PCR (RT-PCR) and fragment analysis, for detection of t (X; 18) (p11; q11) translocation in synovial sarcomas

Background: Synovial sarcoma (SS) is an aggressive, but a relatively chemosensitive soft tissue sarcoma, characterized by a specific, t (X;18)(p11;q11) translocation, leading to formation of SS18–SSX chimeric transcript. This translocation can be detected by various techniques, such as fluorescence in-situ hybridization (FISH), reverse transcriptase PCR (RT-PCR) and fragment analysis. Objectives: To compare the results of detection of t (X;18)(p11;q11) translocation, across three different platforms, in order to determine the most optimal and sensitive technique. Methods: Formalin-fixed paraffin embedded (FFPE) tissue sections of 45 soft tissue sarcomas were analyzed, including 16 cases of SS confirmed by histopathology, immunohistochemistry and molecular technique (s)(Group 1); 13 cases, wherein SS was one of the differential diagnosis, preceding molecular testing (Group 2) and 16 cases of various other sarcomas (Group 3). Various immunohistochemical (IHC) markers studied, including INI1/SMARCB1. All cases were tested for t (X;18) translocation, by fragment Analysis, FISH and RT-PCR. Results: There were 23 cases of SS, including 16 of group 1 and 7 of group 2. By fragment analysis, t (X;18)(p11;q11) translocation was detected in 22/23 cases (95.6%). By FISH, SS18 gene rearrangement was detected in 18/22 cases (78.2%), whereas by RT-PCR, SS18-SSX transcripts were detected in 15/23 cases (65.2%). Immunohistochemically, a unique “weak to absent”/reduced INI1 immunostaining pattern was exclusively observed in 12/13 cases of SS (92.3%). Fragment analysis and FISH were relatively more sensitive techniques. Unique “weak to absent”INI1 immunoexpression significantly correlated with positive t (X;18) translocation results (P = 0.0001). Conclusion: The present study constitutes first such study from our subcontinent. Fragment analysis is a promising technique for detection of t (X;18)(p11;q11) translocation. FISH and INI1 immunostaining pattern were also relatively more sensitive, over RT-PCR.

Epithelioid sarcoma of paratesticular region: A case report of an unusual case

Primary tumors of the paratesticular region are rare, with sarcomas constituting a major proportion, particularly in the old age. The paratesticular region consists of mesothelial, various epithelial, and mesenchymal cells and may therefore give rise to a variety of tumors. Epithelioid sarcoma usually occurs at the distal extremities of young adults. The proximal-type variant is characterized by a more aggressive course and resistance to treatment. We herein report a case of 32 years male with scrotal swelling diagnosed as proximal-type epithelioid sarcoma of paratesticular region after histopathological examination and immunohistochemistry. To the best of our knowledge, this is only the second case of proximal epithelioid sarcoma of paratesticular region in the English literature. As these tumors are rare, it has been difficult to establish their optimal treatment. Also, these can be easily misdiagnosed as other epithelioid lesions.

Poorly-differentiated chordoma with INI1 loss: a clinicopathologic study / 中华病理学杂志

Objective@#To analyze the clinicopathologic characteristics of poorly-differentiated chordoma with INI1 loss in children and to discuss the differential diagnosis.@*Methods@#The clinical, radiological, histopathological profiles and molecular pathologic characteristics of two pediatric poorly differentiated chordoma cases with INI1 loss were reviewed.@*Results@#The patients were a girl and a boy. Both lesions involved the slope. Both patients were presented with progressive muscle weakness or neck pain. Radiological examination showed clivus bone destruction and compression of the brain stem and cervical spinal cord. Histologically, the tumor cells lacked typical organization and were associated with inflammatory cells infiltration. On high power field, the tumor cells were ovoid or fusiform with prominent atypia, vacuolated nuclei and prominent nucleoli. By immunohistochemistry, the tumor cells expressed cytokeratin, epithelial membrane antigen, brachyury and were negative for INI1. In both cases, INI1 gene deletion was detected by FISH.@*Conclusions@#Poorly-differentiated chordoma with INI1 loss mainly occurs in children. The morphology is different from classical chordoma.INI1 gene deletion is detectable by FISH. It can be distinguished from atypical teratoid/rhabdoid tumors and other neoplasms by the identification of nuclear brachyury expression. The loss of INI1 expression in poorly-differentiated chordoma might be associated with a poorly-differentiated morphology and an adverse prognosis.

Renal and extra-renal rhabdoid tumor:analysis of 4 cases and lit-erature review / 中国肿瘤临床

Objective:To analyze the clinico-pathological characteristics, pathological diagnosis, and treatment of rhabdoid tu-mor. Methods:The medical records of four rhabdoid tumor patients that were admitted to the Tianjin Medical University Cancer Insti-tute and Hospital since 2000 were analyzed based on existing literature. Results:In one of the four cases, the tumor originated from the kidney, whereas in the other three, the tumor occurred from extra-renal soft tissues. Histologic analysis revealed that the tumor cells were loosely arranged with diffuse growth, vesicular nuclei, dyed cytoplasm, visible eosinophilic inclusions, and more nuclear fission. The results of immunohistochemical staining showed that the vimentin and epithelial membrane antigen were positive, whereas CK, CD99, CD34, and S-100 were positive at different degrees. MyoD1, Desmin, and INI-1 were negative. Conclusion:Rhabdoid tumor is rare and highly aggressive. It occurs mainly in the kidney and can also be found in other systems. The unique pathological form and im-munohistochemical staining observed on the tumor can be used as reference for diagnosis.

Adult-Onset Sellar and Suprasellar Atypical Teratoid Rhabdoid Tumor Treated with a Multimodal Approach: A Case Report

We report a very rare case of sellar and suprasellar atypical teratoid rhabdoid tumor (ATRT) in a 42-year-old female patient. The tumor was removed subtotally with a transsphenoidal approach. Histopathologic study showed rhabdoid cells with prominent nucleoli and abundant cytoplasm. Immunohistochemistry for INI1 was completely negative in the tumor cells, consistent with ATRT. After surgery, she received radiotherapy including spinal irradiation with proton beam therapy and subsequent chemotherapy, with no evidence of recurrence for more than 2 years. Up to date, this is the 8th case of an adult-onset ATRT in the sellar or suprasellar region. Despite its rarity, ATRTs should be considered in the differential diagnosis of an unclear malignant sellar or suprasellar lesion in adult patients and the treatment strategies for adult ATRT patients could be differentiated from those of pediatric ATRT patients.

Rhabdoid Carcinoma of the Rectum

Rhabdoid colonic tumors are very rare lesions with just a few publications describing such neoplasms. Even more unusual for these lesions are their primary rectal locations, with only two brief case reports having been published on that subject to date. We present a case of a composite rhabdoid rectal carcinoma in a 49-year-old male. The tumor behaved very aggressively, with rapid patient demise despite radical surgery and intensive postoperative chemotherapy (FOLFIRI [folinic acid {leucovorin}, fluorouracil {5-fluorouracil}, and irinotecan] and FOLFOX4 [folinic acid {leucovorin}, fluorouraci {5-fluorouracil}, and oxaliplatin]). Pathologic examination was supportive of a rhabdoid carcinoma, with a compatible immunohistochemical profile, demonstrating synchronous expression of vimentin and epithelial markers in the tumor cells. In addition, BRAF V600E gene mutation, together with a wild-type KRAS gene, was identified, and no evidence of microsatellite instability based on MLH1, MSH2, MSH6, and PMS2 immunophenotypes, i.e., no loss of expression for all 4 markers, was observed. Our reported case confirms previously published observations of the clinical aggressiveness and the poor therapeutic response for rhabdoid tumors.