Prostatic stromal tumour of uncertain malignant potential

A rare type of prostate tumor with uncertain malignant potential

Prostatic stromal tumor of uncertain malignant potential (STUMP) is a rare type of prostate tumor characterized by stromal proliferation with atypical features that do not meet the criteria for prostatic sarcoma. These tumors are part of a spectrum of prostatic stromal proliferations, which range from benign stromal nodules to malignant stromal sarcomas.

Pathology

Prostatic STUMP is defined by its histological appearance, which includes a proliferation of stromal cells with varying degrees of cellular atypia and mitotic activity. The tumor may exhibit a range of architectural patterns, including phyllodes-like, hypercellular, and myxoid types. The diagnosis of STUMP is challenging due to its overlapping features with other prostatic lesions.

Histological image of a prostatic stromal tumor of uncertain malignant potential

Histological Features

The histological examination of STUMP reveals a proliferation of spindle cells with varying degrees of cellularity and atypia. The stromal component may show a range of patterns, including:

• Phyllodes-like pattern: Resembling phyllodes tumors of the breast, with leaf-like stromal projections.
• Hypercellular pattern: Increased cellularity with minimal atypia.
• Myxoid pattern: Abundant myxoid stroma with scattered stromal cells.
• Collagenous pattern: Dense collagenous stroma with scattered atypical stromal cells.

Clinical Presentation

Patients with prostatic STUMP may present with lower urinary tract symptoms, such as urinary frequency, nocturia, and dysuria. Some patients may be asymptomatic, and the tumor is discovered incidentally during evaluation for other prostatic conditions.

Diagnosis

The diagnosis of prostatic STUMP is primarily based on histopathological examination of prostate tissue obtained via prostate biopsy or transurethral resection of the prostate (TURP). Immunohistochemical staining may aid in differentiating STUMP from other prostatic lesions.

Treatment

The management of prostatic STUMP is not well-defined due to its rarity and uncertain malignant potential. Treatment options may include:

• Surgical resection: Complete surgical excision may be considered, especially if the tumor is causing significant symptoms.
• Active surveillance: In cases where the tumor is asymptomatic and the risk of progression is deemed low, active surveillance with regular follow-up may be appropriate.

Prognosis

The prognosis of prostatic STUMP is variable and depends on the specific histological features and the presence of any malignant transformation. Some cases may remain indolent, while others may progress to prostatic stromal sarcoma.

Related pages

• Prostate cancer
• Benign prostatic hyperplasia
• Prostatic intraepithelial neoplasia