American Urological Association - Other Rare Mesenchymal Tumors and Sarcomas
Other Rare Mesenchymal Tumors and Sarcomas
Tumors with Neural Differentiation
- May occur in patients with neurofibromatosis I (von Recklinghausen disease) and probably arise from the adjacent pelvic autonomic plexus.
- Mostly are young patients (1 month to 35 years old) and had neurofibromas in other organs including the skin.
- Present as mass lesion or with obstructive symptoms.
- Most prostate neurofibromas also involved the bladder.
- Morphology of prostatic neural tumors (neurofibroma or schwannoma) are similar to those in somatic tissues (image A) and can be confirmed by S100+.
- Hemangiomas may arise along the posterior urethra; very rare within the prostate.
- May cause hematuria, hematospermia and/or post ejaculation hematuria.
- Posterior urethral hemangiomas are seen in patients 29-80 years old (mean 57) and cystoscopically, appear as small sessile varicosities between the verumontanum and external sphincter.
- Histologically, majority are cavernous hemangioma.
- Prostatic angiosarcoma (AS) is also rare and consists of proliferating vascular channels lined by atypical spindle to epithelioid cells (image B).
- Diagnosis of AS is confirmed by endothelial markers such as factor VIII-related antigen, CD34+ or CD31+.
- Other rare sarcomas reported in the prostate include synovial sarcoma (with t(X;18)(p11.2;q11.2) or SYT-SSX fusion), primitive neuroectodermal tumor (PNET) (with t(11;22)(q23;q12) PNET or EWS/FLI1 transcript) and malignant fibrous histiocytoma (MFH).