Malignant fibrous histiocytoma in a patient presenting with urinary system symptoms

Imaging and Clinical Findings of Primary Malignant Fibrous Histiocytoma of the Urinary Bladder: A Case Report

Primary malignant fibrous histiocytoma (MFH) is a malignant tumor of mesenchymal origin that rarely occurs in the urinary tract, particularly in the urinary bladder. Unlike urothelial carcinoma, which accounts for most bladder cancers, it occurs in the submucosal portion of the bladder wall and consists of the lamina propria, muscularis propria, and adventitia. It is presumed to originate from poorly differentiated pluripotent mesenchymal cells in which fibroblasts and histiocytes are partially differentiated. Radiologically, it is known as the "non-papillary tumor" and is commonly diagnosed as a large mass without necrosis, which shows invasion beyond the muscularis propia. Although the prognosis of this rare malignancy depends on pathological parameters, it generally has a poor prognosis with high local tumor recurrence. Here, we present a case of primary MFH in the urinary bladder with clinical symptoms of lower abdominal pain without gross hematuria that recurred rapidly and showed an aggressive disease course.

A rare case of primary malignant fibrous histiocytoma: a sarcoma of the kidney

Background

Primary malignant fibrous histiocytoma of the kidney (MFH) is an extremely rare tumor which is indistinguishable from its’ mimics in particular renal cell carcinoma (RCC) by clinical features and preoperative imaging evaluation. Due to its high predilection to local recurrence and distant metastases, early diagnosis has great value.

Case presentation

Herein, we describe a 62 year-old man with a 3-month history of abdominal discomfort and a palpable right loin mass whom computerized tomography (CT) showed a large heterogeneous solid mass in the right kidney. With the suspicious to RCC; the patient underwent radical nephrectomy. However, histopathological report revealed pleomorphic-storiform malignant fibrous histiocytoma. Immunohistochemistry study was also confirmed the diagnosis of MFH. Six month follow up showed no evidence of any recurrence.

Conclusions

The therapeutic options for MFH differ from other renal tumors, hence histopathology and immunohistochemistry studies are required to establish a definite diagnosis of the disease. Despite of progress made in clinical studies and advances in diagnostic modalities, early diagnosis of MFH has not achieved yet. Further studies and accumulated experience with renal MFH are required to determine the approach to prolong survival in selected cases along with management and prognostic factors of such tumors.