SAR DFP Case of the Week Janesh Lakhoo MD, MS, Sandeep Arora MD

Department of Radiology Body Section Vanderbilt University Medical Center Case 1 History

• 68 y/o male complaining of acute on chronic intermittent weak urinary stream requring multiple foley catheter placements • PMHx: HTN, BPH • PSHx: , cystoscopy, • Social Hx: Never smoker • Medications: Finasteride, tamsulosin, lisinopril/HCTz CT Pelvis With Contrast

Findings: Enlarged, heterogeneous prostate measuring 5 x 5 x 5.6 cm Transrectal US Guided Prostate

Biopsy Location Result Gleason Score

Left Base Adenocarcinoma 4+4 = 8

4+4 = 8 Left Mid Adenocarcinoma

4+4 = 8 Left Apex Adenocarcinoma

Adenocarcinoma w/ 4+5 = 9 Right Base Small Cell Carcinoma perineural inv.

5+5 = 10 (2/3 cores) Right Mid Adenocarcinoma %+4 = 9 (1/3 cores)

4+4 = 8 (2/3 cores) Right Apex Adenocarcinoma Small Cell Carcinoma FDG PET

Findings: FDG Avid metastasis to left inguinal lymph node. Metastatic Lesion: Small Cell or Adenocarcinoma?

• Given both adenocarcinoma and small cell cancer on prostate biopsy, we were asked to determine what type of metastatic lesion this was.

• Initially a biopsy was requested, but a Ga-Dotatate study was recommended instead. Ga68-Dotate Study

• Dotatate binds to somatostatin receptors unlike FDG which is taken up by metabolically active cells

• Somatostatin receptors are found in neuroendocrine tumors small cell carcinoma, and non-small cell lung cancers

• Normal physiologic uptake (in order of highest intensity):

spleen → adrenals → kidneys → pituitary → liver, thyroid salivary glands Ga68-Dotate Study

Findings: Multiple metastatic lesions showing Ga68-Dotate uptake in the previously identified FDG avid lymph node and within multiple other lymph nodes, and bone throughout the patient. Small Cell Carcinoma of the Prostate (SCCP) • Patient had predominantly SCCP metastases as opposed to adenocarcinoma that were not FDG avid.

• SCCP accounts is rare and accounts for <1% of all prostate cancers

• Patients usually present with symptoms and in contrast to adenocarcinoma, serum prostatic sepcific antigen (PSA) is not predictive of disease.

• Patients can present with abnormal lab findings relating to paraneoplastic syndromes.

1. Weprin, Samuel, and Paul Yonover. Small Cell Carcinoma of the Prostate: A Case Report and Brief Review of the Literature. Case Reports 13 (2017): 61–62. Small Cell Carcinoma of the Prostate (SCCP) • SCCP metastasizes early in its course with brain metastases being common unlike adenocarcinoma. Given this, survival is poor with median survival of <12 months.

• SCCP is managed with cytotoxic chemotherapy and locoregional therapy including radiation and resection. Androgen deprivation can also be included if concomitant adenocarcinoma.

• Of note, most patients with adenocarcinoma treated with androgen deprivation will eventually develop resistant with neuroendocrine characteristics including increased somatostatin receptor production. Thank you