Sarcomatoid carcinoma of the prostate presenting as bilateral cervical lymphadenopathy: a rare case report

Background: Sarcomatoid carcinoma (also called carcinosarcoma in the latest WHO classification 2016) of the prostate gland is a biphasic malignant neoplasm which exhibits epithelial and mesenchymal differentiation [1]. Sarcomatoid carcinoma is a rare tumour, considered as a variant of acinar adenocarcinoma in the WHO classification, with less than 200 reported cases in the literature to date [2]. Sarcomatoid carcinoma of prostate presenting with bilateral cervical lymph node deposits as the first clinical manifestation, is even rarer, and reported cases were not found in the literature; hence, this is the first case report of such, to the best of our knowledge. Case presentation: We report a case of sarcomatoid carcinoma of the prostate in a 72-year-old Sri Lankan man who presented with bilateral cervical lymphadenopathy. He had hard nodular prostate on digital rectal examination (DRE). Ultrasound scan of abdomen (USS) revealed the presence of paraaortic lymphadenopathy, in addition. The excision biopsy of the right cervical lymph node revealed deposit of a carcinoma of epithelioid histomorphology, which showed patchy strong positivity for immunohistochemical marker (IHCm), PSA. His serum PSA value was 48 ng/ml (reference <5.40 ng/ml). Contrast-enhanced computed tomography (CECT) showed mildly enlarged prostate gland with irregular outline, sclerotic lesions in cervico-thoracic and lumbosacral vertebrae and generalized lymphadenopathy. Transrectal ultrasound guided biopsy of the prostate revealed sarcomatoid carcinoma. Disseminated sarcomatoid carcinoma of prostate was diagnosed. The patient has undergone bilateral orchidectomy, marking a serum PSA value of 5.4 ng/ml two months thereafter. He is surviving for six months after diagnosis and is currently under chemotherapy with docetaxel for the disseminated disease. Conclusion: Sarcomatoid carcinoma can present with cervical lymphadenopathy with absent lower urinary tract symptoms. In elderly patients with cervical lymphadenopathy, serum PSA, DRE and trans-rectal ultrasound scan are advocated to rule out prostate cancer. Immunohistochemical markers are required for the diagnosis of primary tumour and secondary deposit of sarcomatoid carcinoma of prostate.