Immunohistochemical Analysis of CD99 and PAX8 in a Series of 15 Molecularly Confirmed Cases of Ewing Sarcoma.

Ewing sarcomas are an uncommon group of malignant neoplasms. A multidisciplinary approach is highly recommended to reach a correct diagnosis, considering the clinical, radiological, and histopathological aspects. Since in up to 90% of cases, the translocation t (11; 22) (q24; q12) occurs resulting in a chimeric fusion transcript EWSR1-FLI-1. The pathologist has several tools in addition to conventional techniques (hematoxylin and eosin), such as immunohistochemistry, which plays a very important role in the differential diagnosis. We present a series of 15 cases of molecularly confirmed ES, in which we found a sensitivity of 100% for CD99 and 80% for PAX8 by immunohistochemistry. This indicates a high sensitivity; however, it is known that both CD99 and PAX8 are also expressed in other tumours. Therefore, molecular confirmation should be performed in all cases.

[Bladder schistosomiasis. Report of a case]. / Esquistosomiasis vesical. Presentación de un caso.

OBJECTIVES: We report an additional case of schistosomiasis of the urinary bladder, an unusual parasitic infection in our setting, with special reference to the histomorphological findings that permitted its diagnosis. METHODS: Biopsy was performed via cystoscopy and bladder tissue was obtained from an area in the trigone with an abnormal appearance. RESULTS: Microscopic examination of the biopsy specimen revealed eggs of the parasite Schistosoma haematobium. CONCLUSIONS: The present case shows the importance of close collaboration between clinicians and pathologists and the usefulness of cystoscopy for diagnosis in urological patients.

[Idiopathic calcinosis of the scrotum. Cytohistologic diagnosis in biopsy and puncture samples]. / Calcinosis idiopática del escroto. Diagnóstico citohistológico en biopsia y material de punción.

OBJECTIVE: To report an uncommon case of idiopathic calcinosis of the scrotum. METHODS/RESULTS: A case of idiopathic scrotal calcinosis in a 50-year-old male who presented with multiple hard masses in the scrotum is described. Cytological (fine needle aspiration) and histological (biopsy and resection) analyses of these lesions were performed. CONCLUSIONS: Although the etiopathogenesis of scrotal calcinosis remains unknown, the involvement of a dystropic mechanism has recently been described. The usefulness of fine needle aspiration, a method that has gradually been included in the study of testicular pathology, is underscored.