Malignant neurofibroma of the urinary bladder

Primary Urethral Malignant Peripheral Neural Sheath Tumor in a 58-Year-Old Female in the Absence of Neurofibromatosis Type 1

A malignant peripheral neural sheath tumor (MPNST) is a malignant soft tissue neoplasm with cellular origin arising from the outer lining of peripheral nerves. Approximately 10 cases have been identified to date where the lower urinary tract was affected. We discuss the case of a female patient that presented with primary MPNST that arose in the urethral tract in the absence of neurofibromatosis type 1 (NF1) or prior malignancies. This patient presented with pain and acute urinary tract symptoms secondary to urethral obstruction by a protruding vaginal mass. The patient underwent an incomplete initial resection to alleviate symptoms and to obtain a tissue diagnosis. Three months after the first hospitalization, the patient was re-hospitalized due to the recurrence of symptoms and subsequently underwent a complete tumor excision. The initial resection showed a 7.0 x 4.5 x 4.5 cm aggregate of tan-red to gray tumor masses. Microscopic examination showed a spindle cell neoplasm with malignant cytological features (hypercellularity, atypical mitoses, nuclear pleomorphism, and indistinct borders). Tumor cells stained positive for SOX10, S-100 (10% of tumor), with a "mosaic pattern" of H3K27ME3 (50% of tumor nuclei positive). Other lineage-specific and keratin markers stained negative. In the absence of other patient known primaries, the findings were consistent with a primary MPNST of the urinary tract. Residual tumor was identified on MRI scans one month after the follow-up. The completely excised tumor specimen on the second admission showed identical morphology when compared to the first specimen. While MPNSTs typically carry a poor prognosis, knowledge of behavior and prognosis of primary MPNSTs in the bladder is limited, due to the few relative numbers of available case reports. Further research is needed to study the clinical behavior, morphology, immunophenotypes, and genetics of primary MPNSTs arising from the lower urinary tract.

Malignant peripheral nerve sheath tumour in an unusual location of the urinary bladder: case report and review of literature

Background

Malignant peripheral nerve sheath tumour (MPNST) is a rare malignant soft tissue neoplasm of ectomesenchymal origin. They usually arise from a major or minor peripheral nerve branch or its sheath and also from somatic soft tissues. The most common sites of origin include the extremities and trunk but can sometimes arise an unusual site resulting in the demise of the patient before any intervention.

Case presentation

We report a case of 58-year-old male who presented with complaints of weight loss of a year duration, abdominal swelling of 10 months duration and easy fatigability of 3 weeks duration. Digital rectal examination revealed a huge firm mass 6 cm from the anal verge which was non-tender. Abdomino-pelvic ultrasound scan revealed an irregular heterogeneous mass in the posterior wall of the urinary bladder measuring 15.1cmx 14.0 cm with bilateral dilatation of the renal pelvi-calyceal system and ureters. His clinical condition continued to deteriorate while on hospital admission, and he died on the12th day of admission. Post-mortem examination showed a rough ovoid tumour mass firmly adherent to the posterior wall of the bladder with compression of both ureters. Histological and immunohistochemical analysis of the tumour revealed the diagnosis of a MPNST. The final anatomical diagnosis and cause of death was that of a malignant peripheral nerve sheath tumour of the urinary bladder with obstructive uropathy and severe sepsis.

Conclusion

MPNST can arise at unusual sites other than its common location in the extremities and the existence of neurofibromatosis may not be present. High index of suspicion of MPNST should be raised in rapidly growing painless tumour in and around a nerve tissue. Prompt radio-imaging with biopsy and expert immunohistochemical analysis of lesions will lead to early diagnosis and intervention. Molecular targeted therapies following surgery for MPNST should be developed to improve prognosis and patient outcomes.

Pelvic neurofibroma

A 58-year old male presented with a hard lump in lower abdomen extending into pelvis. Clinical examination and computed tomography scan revealed pelvic retroperitoneal mass. Patient underwent exploratory laparotomy - revealing a well encapsulated retroperitoneal mass extending up to coccyx, posterior to the urinary bladder. It had displaced the recto-sigmoid colon and urinary bladder to the right. Histopathological findings revealed a neurofibroma. Pelvic neurofibromas are known to arise from certain pelvic organ. However, present case ruled out any organ involvement both on imaging and intraoperatively. This shows that these tumors can arise de novo also. A brief case report and review of literature is presented.