A case of a sporadic malignant peripheral nerve sheath tumor of the urinary bladder with concomitant in situ urothelial carcinoma treated by transuretheral resection.

Malignant peripheral nerve sheath tumor (MPNST) of the urinary bladder is a very rare clinical entity. The association of such a tumor with urothelial carcinoma is even more unusual. Differential diagnosis between coexisting two distinct primary tumors and carcinosarcoma of the urinary bladder is very important as both the treatment and prognosis vary widely. Herein, we report a case of an MPNST with a concomitant in situ urothelial carcinoma in a 53-year-old man. To our knowledge, this is the first documented case of MPNST of the bladder that is treated by transuretheral resection which is in contrast with the previous reports that used cystectomy.

Papillary renal cell carcinoma with lipocyte-like cells: A rare morphological variant or an indication of aggressiveness.

Papillary renal cell carcinoma (PRCC) is the second most common carcinoma of the kidney, which is classified into two types. Type 1 displays single layer of cells with scanty pale cytoplasm and type 2 has pseudostratified high-grade nuclei with eosinophilic cytoplasm. Recently, apart from these two types, oncocytic PRCC and clear-cell PRCC have been described. To the best of our knowledge, lipocyte-like cells have not yet been reported to accompany any subtypes of renal cell carcinoma. Herein, we report a case of PRCC with lipocyte-like cells and sarcomatoid features. Lipocyte-like cells might represent a special type of PRCC or this feature may be an indication of poor prognosis regarding its association with sarcomatoid change.