Melanoma of the prostate with metastases to lung

Case contributed by Assoc Prof Frank Gaillard


Patient presented with urinary symptoms and retention.

Patient Data

Age: 40 years
Gender: Male

Pelvic ultrasound

The prostate is enlarged, has heterogeneous echotexture, and shows lobulated contours growing into the bladder floor. 


CT Chest, Abdomen, and Pelvis

Non-contrast CT scans showing an enlarged prostate with a mass like appearance that invades the bladder and likely the seminal vesicles. Multiple pelvic enlarged lymph nodes. There is upstream mild hydroureter and hydronephrosis. Also, multiple bilateral pulmonary metastases. 

Case Discussion

Ultrasound of the prostate demonstrates a large irregular prostate, bulging into the base of the bladder, which itself appears thick walled, suggesting hypertrophy. 

CT, performed only with oral contrast (due to renal impairment) confirms the abnormality. The prostatic mass has ill-defined margins with evidence of invasion into the seminal vesicles. Numerous enlarged pelvic nodes are present and both kidneys are hydronephrotic. 

The lungs contain innumerable pulmonary metastases

The appearances are those of a malignant prostatic mass (stage IV). The differential includes advanced prostate cancer, TCC of the bladder base, SCC of the urethra, sarcoma, primary melanoma of the prostate


Microscopic description: The sections show cores of prostatic parenchyma infiltrated by a malignant epithelioid and spindled tumor showing abundant cytoplasmic melanin pigment, indicating a diagnosis of melanoma.   Foci of tumor necrosis are present.

Immunohistochemical stains have been performed on this tumor. The tumor cells are positive for  S100, HMB-45 and Melan A,  confirming the diagnosis of melanoma.

Final diagnosis: Prostate TRUS biopsies : melanoma

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Case information

rID: 11016
Published: 9th Oct 2010
Last edited: 13th Aug 2019
System: Urogenital
Inclusion in quiz mode: Included

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