Mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney is a recently described entity in the World Health Organization (WHO) 2004 classification and has a relatively indolent behavior. Sarcomatoid differentiation has been well documented in most histologic variants of renal cell carcinoma and its presence is known to have a worse prognosis. Its occurrence in an otherwise benign MTSCC is extremely rare. Here, we report a unique case of MTSCC in a 64-year-old patient with multiple areas of high-grade spindle cells and large areas of necrosis in it. The patient had a rapidly fatal clinical outcome.

Plasmablastic lymphoma (PBL) is an aggressive and rare variant of diffuse large B-cell lymphoma, which is thought to occur in immunocompromised individuals, specifically HIV-positive patients. We report the case of a 27-year-old Saudi male with PBL. The patient had a low CD4 count at presentation, however, he was HIV negative at the time of diagnosis; also Human herpesvirus-8 was negative on immunohistochemical stain, but Epstein–Barr virus showed expression in scattered cells through the utilization of EBV-EBER.

We describe a unique case of perivascular epithelioid cell tumors PEComas occurring as mediastinal and left renal soft tissue masses discovered incidentally in a five-year-old Tuberous Sclerosis patient upon presentation to the emergency department for upper respiratory illness. The radiographic features were non-specific. However, the similar CT characteristics of both lesions and background history raised the suspicion of a synchronous mesenchymal tumor, and histopathology confirmed the diagnosis. The rarity of these tumors in the pediatric population and lack of specific diagnostic criteria impose reporting the case and emphasize the need for further research on imaging features of such tumors.