Primary squamous cell carcinoma is an uncommon tumor of the prostate gland. We report a 77-year-old male patient with urinary frequency and constipation. Fine needle biopsy from prostate was suspicious of squamous cell carcinoma of the prostate. Whole body positron emission tomography/computed tomography scan revealed high fluorodeoxyglucose uptake in prostate gland. Transurethral resection confirmed the diagnosis. In contrast to prostatic adenocarcinoma, high fluorodeoxyglucose accumulation was observed in the primary tumor of the prostate gland.
Primary squamous cell carcinoma of the prostate is a rare neoplasm of prostate gland and comprises 0.5–1% of all prostatic carcinomas [
The initial diagnostic procedure for a patient with suspected prostate cancer is multiple site blind prostate biopsies. Among currently available nuclear medicine studies, positron emission tomography (PET) has some potential to detect primary tumor in prostate cancer. In prostatic adenocarcinoma, however, fluorodeoxyglucose (FDG) is inferior to other PET tracers like choline and acetate and conducted studies using FDG PET in localized prostate cancer reported disappointing results [
Herein, we report a patient with squamous cell carcinoma of prostate, in whom high FDG accumulation was observed in primary tumor site. The difference of FDG affinity between prostatic adenocarcinoma and squamous cell cancer of prostate is discussed and the literature is reviewed.
A 77-year-old man admitted to our hospital with complains of constipation and hesitancy. He had decreased urinary output and severe constipation for 5-6 months. Clinical examination revealed an enlarged and firm prostate. Laboratory evaluation showed that serum prostate specific antigen (PSA) levels were in normal levels (4.3 ng/mL, normal: 0–4.5 ng/mL). However, serum creatinine and urea levels were 2.42 mg/dL (normal: 0.4–1 mg/dL) and 87.5 mg/dL (normal: 11–36 mg/dL), respectively. The uroflowmetry test was compatible with an obstructive pathology. Since the patient has severe constipation, a rectosigmoidoscopy and fine needle biopsy were performed which was suspicious for squamous cell carcinoma of the prostate. Fluorodeoxyglucose positron emission tomography computed tomography (FDG PET/CT) was performed for staging. Dual modality PET/CT examination was obtained after intravenous administration of 370 megabecquerel FDG with using an integrated scanner (Biograph mCT, Siemens). The PET scan was started immediately after unenhanced CT. PET/CT examination revealed an increased 18F-FDG uptake in the prostate expanding through the rectum with a maximum standardized uptake value (SUVmax) of 29.73 (Figure
Coronal (a), sagittal (b), transaxial (c) CT, fused PET/CT (d) and coronal (e), sagittal (f), transaxial (g) PET, and MIP (h) images of the patient. Increased FDG uptake extending to the rectal wall was observed in the posterolateral part of the prostate gland ((d), arrow).
(a) Tumor cells with atypical, pleomorphic nuclei, prominent nucleoli, and cytoplasmic keratotic features infiltrating prostatic stroma (HEx200). (b) Tumor island with central necrosis is seen near a prostatic duct (HEx200).
The optimal treatment of the primary squamous cell carcinoma is still unknown. We planned to start with pelvic radiotherapy. The radiotherapy dose was planned as 50.4 Gray (Gy) to the pelvic region with pelvis box technique, a 16 Gy boost dose to the prostate gland, and a 10 Gy boost dose to the metastatic lymph nodes. However, at 6th day of radiotherapy the patient was admitted to the emergency service with a complaint of severe nausea and vomiting. Laboratory work-up revealed a creatinine level of 3, 35 mg/dL and serum urea levels of 248 mg/dL with metabolic acidosis, thought to be secondary to acute kidney injury. The patient consulted the nephrology department for dialyses; he could not continue to the radiotherapy until his metabolic acidosis and vomiting got better. Therefore we gave a break to radiotherapy for a week, and then he continued with his treatment.
The initial diagnostic procedure for a patient with suspected prostate cancer is multiple site blind prostate biopsies [
Squamous cell carcinoma of prostate is extremely rare clinical and pathological entity. It usually presents with lower urinary tract symptoms or symptoms related to bony metastases. In terms of clinical markers, in contrast to ordinary prostate adenocarcinoma, the squamous variant does not result in elevated levels of prostatic acid phosphatase (PAP) or PSA [
To date, few cases with primary squamous cell carcinoma of the prostate have been reported in the literature [
Histogenesis of squamous cell carcinoma remains unclear. Some authors suggest that the prostatic urethral urothelium is the origin of squamous cell carcinoma [
In prostatic adenocarcinoma, primary cancer shows relatively low FDG uptake and the same is true for nodal metastases. Limited sensitivity of FDG for the assessment of sclerotic bone metastases of prostate carcinoma has also been noted [
In conclusion, squamous cell carcinoma of prostate should be considered in the differential diagnosis of abnormal FDG uptake of prostate. Apart from staging, in contrast to prostatic adenocarcinoma, FDG PET/CT may also play a role as a noninvasive test to direct biopsy for squamous cancer of prostate, as well.
The authors declare that there is no conflict of interests regarding the publication of this paper.