Secondary Signet Ring Cell Carcinoma of Prostate
A 74-year-old male patient presented with frequency of micturition, dysuria, and features of urinary outlet obstruction developing progressively over a period of last 3 months. He was a smoker, occasional drinker, and complained of no other features of clinical interest except infrequent dyspepsia. Transrectal ultrasonography showed Grade III prostatomegaly measuring 5.5×4.2×4.8cm (58g), with suspicious hypoechoic areas in the peripheral zone and residual urine of 80 ml. Serum total PSA level was 9.71 ng/ml and free-to-total PSA ratio was 10.8. On digital rectal examination the prostate was elastic, slightly hard, painless, and with prominent retroprostatic sulci. Blood examination showed microcytic hypochromic anemia and an elevated erythrocyte sedimentation rate. Chest X-ray revealed no abnormalities.\nCystoscopic examination found no primary abnormality of the bladder and extensive transurethral resection of prostate (TURP) was performed under anesthesia with resultant specimen measuring 45 g. Histopathology revealed nests and singly infiltrating poorly differentiated, hyperchromatic, pleomorphic adenocarcinoma cells majority of which were of signet ring morphology [Figures –]. Individual cells and cell nests were seen lying haphazardly among bundles of smooth muscle fibers and also within lymphovascular spaces but no perineural invasion, mucinous fibroplasia or glomerulations were noted. Initial diagnosis of signet ring variant of invasive prostatic adenocarcinoma with Gleason score 4+5=9 was thought of but IHC for PSA [ (inset)] and Carcinoembryonic Antigen (CEA) were simultaneously performed as primary prostatic signet ring cell adenocarcinoma is rare and it is mandatory to exclude other mucinous tumors of non-prostatic origin based on morphology and immunohistochemistry and if necessary using clinical information.[] Both the immunostains showed negative results. The globoid optically clear cytoplasm of the signet ring cells were stained positively with Alcian blue at pH 2.5 confirming the contents as acid mucin [ (inset)]. Gastric endoscopic biopsy was subsequently performed 2 weeks after TURP and histopathology showed infiltrating signet ring cell carcinoma of stomach. Computerized tomography showed no hepatic metastases and only enlarged regional lymph nodes. Radical gastrectomy was done and follow-up chemotherapy was instituted. The patient is doing well after 6 months of the initial prostatectomy.