Foamy gland carcinoma is a variant of prostatic acinar adenocarcinoma characterized by abundant, foamy cytoplasm, frequently showing small, pyknotic nuclei. Foamy gland carcinoma may be deceptively benign appearing and missed on needle biopsy. Most foamy gland carcinomas are Gleason score 6 or 7, although Gleason score 8-10 carcinomas have been reported. Its occurrence is extremely rare. Prognosis depends on the Gleason score and the presence or absence of perineural or extra prostatic extension. Treatment modalities of foamy gland adenocarcinoma are a similar to that of usual acinar adenocarcinoma. We report an extremely rare case of foamy gland adenocarcinoma of the prostate associated with high-grade prostatic intraepithelial neoplasia lesion on TRUS core needle biopsy in a 78-year-old man presented with history of lower urinary tract symptoms (LUTS) during the last 6 months. Digital rectal examination: the prostate was enlarged, firm in consistency, non-tender, but with a nodule on its left base. Serum prostate-specific antigen (PSA) was 19 ng/mL. Prostate RMI showed a PIRADS 4 lesion on the left base of the prostate. TRUS-guided core biopsy was performed. Pathology report of the prostate cores found foamy gland adenocarcinoma; Gleason score 9 (4 +5) with presence of high-grade PIN lesion. The Bone scan and chest/abdomen CT scan were unremarkable. There were a significant relief of his LUTS under alpha-blockers. After discussion of all the management options, the patient chose a simple surveillance with a close follow-up for LUTS and PSA every 3months and thereafter acting accordingly.