Malignant solitary fibrous tumour of the prostate with a concomitant prostatic adenocarcinoma - A case report and review of the literature

ABSTRACT

Solitary fibrous tumor (SFT) of the prostate is a rare mesenchymal neoplasm, and simultaneous occurrence with prostatic adenocarcinoma is rarely reported. We present the case of a 72-year-old man who presented with hematuria and persistent lower urinary tract symptoms despite medical treatment. Imaging revealed an enlarged prostate for which transurethral resection of the prostate was performed. Histopathological examination showed two distinct lesions: a malignant spindle cell neoplasm arranged in fascicles with hypercellularity, moderate to severe atypia, and increased mitotic activity; and a separate glandular lesion consistent with acinar adenocarcinoma of the prostate. On Immunohistochemistry, spindle cells demonstrated diffuse positivity for CD34, Bcl-2, and STAT6, with negativity for pancytokeratin, CK8/18, EMA, TLE-1, desmin, H-caldesmon, and CD117, which supports the diagnosis of SFT. The adenocarcinoma component had a Gleason score of 3+3. The tumour extended to the resection margins and demonstrated metastatic spread to bilateral external iliac and left cloquet lymph nodes, indicating aggressive behavior. The patient subsequently underwent radical prostatectomy with locoregional lymph node dissection. On follow-up imaging, enlarged lymph nodes and a mesenteric mass suspicious for metastasis were noted, though the patient remained clinically stable. This patient’s biopsy highlights the diagnostic challenge posed by spindle cell lesions of the prostate and the importance of correlating morphology with immunohistochemistry and imaging. Awareness of this rare entity, along with careful exclusion of sarcomatoid carcinoma and other spindle cell neoplasms, is essential for accurate diagnosis and appropriate management.