Young patient presents with prostate carcinoma and lesions on bone scan

A 43-year-old male with no significant past medical history and a family history of breast cancer was found to have an elevated PSA of 15.3 on routine screening. The patient had been asymptomatic with no complaints of urinary dysfunction. He denied any systemic symptoms and had no complaints of bony pain.

His rectal exam showed a smooth, non-enlarged prostate with no palpable nodules. Other physical exam observations were within normal limits. He underwent prostatic biopsy showing prostatic adenocarcinoma. The right and the left base showed Gleason 6 (3+3) tumor involving less than 5% of tissue. The right apex showed high-grade prostatic intraepithelial neoplasia. The left apex showed Gleason 6 (3+3) tumor involving 17% of tissue.

A nuclear medicine bone scan showed increased radiotracer uptake in the left humeral head and T8 vertebral body. The patient subsequently underwent MRI of the spine, which revealed diffuse replacement of marrow at T8 level with no extra osseous extension.

A CT-guided biopsy of the T8 lesion was performed to evaluate for metastatic disease. The pathology, however, showed a normal bone marrow with no definite evidence of carcinoma. There was a single cluster of free floating cytokeratin-positive cells that was positive for CAM5.2 and negative for CK AE1/AE3, PSA and prostatic acid phosphatase. These were thought to be non-malignant cells and possibly a contaminant.

Bone scan, posterior projection. The bone scan demonstrates focus of increased update at T8 and left humerus (posterior projection).

Coronal T1W image of the left shoulder shows ill-defined decreased T1 marrow signal in the humeral epiphysis. Coronal STIR image of the left shoulder shows no abnormal marrow edema.

MRI of the prostate confirmed organ-confined disease with a 1.5 cm × 0.9 cm tumor in the right peripheral zone extending along the capsule and a 1.5 cm × 0.8 cm tumor in the left side along the capsule with no evidence of capsule invasion bilaterally. There was no evidence of metastatic lymph node involvement.

At this stage, the patient had clinically T1cN0 disease with a repeat PSA value of 12.8. However, there was a concern about possible metastatic disease to bones. MRI of the left shoulder showed decreased T1 signal in the humeral epiphysis, but no evidence of any focal mass. These findings were similar to that seen in the T8 vertebra. The patient was scheduled to undergo a biopsy of this humeral lesion to evaluate for any evidence of metastatic disease. The CT scan of right shoulder performed in preparation for biopsy showed subarticular cystic lesions characteristic of degenerative disease. Therefore, biopsy was not performed.

Discussion

Prostate cancer is the most common cancer and second-leading cause of cancer-related death in US men, with an estimated 217,730 cases in 2010. The SEER database for patients who died in 2003 to 2007 in the United States found an age-adjusted death rate of 24.7 per 100,000 men per year. The survival is largely influenced by the stage at diagnosis, with almost 100% 5-year survival of patients presenting with organ-confined disease compared with 30% for patients with metastatic disease. The standard treatment options for patients with localized disease include radical prostatectomy and radiation therapy, including external beam radiation/brachytherapy with or without systemic hormonal therapy.

Comparison of left and right humeral head fat signal. Notice the more normal, brighter signal on the right side.

Decreased normal T1 signal on the T8 vertebral body (arrow). No marrow edema on STIR sequence. Increased sclerosis on CT scan (used for biopsy). Photos courtesy of Munir Ghesani, MD

However, treatment for advanced disease is directed toward disease palliation. The standard options include androgen deprivation therapy and chemotherapy for castrate-resistant prostate cancers. Recently, two new drugs were approved for the treatment of metastatic prostate cancer, including abiraterone acetate, a CYP17 inhibitor, and sipuleucel-T (Provenge, Dendreon). Thus, it is imperative that metastatic disease to the skeleton is definitively excluded.

In conclusion, bone scan is an effective and sensitive initial examination in patients with initial diagnosis of prostate cancer and increased PSA values to exclude skeletal metastatic disease. However, there is lower specificity for bone scan-positive lesions, except when there is a pattern of extensive multifocal metastatic disease. Isolated suspected lesions, however, need further radiographic evaluation (and occasionally cytologic sampling) to confirm the presence of metastatic disease and exclude false-positive lesions.

Munir Ghesani, MD, is an attending radiologist at St. Luke’s-Roosevelt Hospital Center and Beth Israel Medical Center, and a HemOnc Today section editor. He is an associate clinical professor of radiology at Columbia University College of Physicians and Surgeons.

Ronald Ennis, MD, is an attending physician and chief of radiation oncology at St. Luke’s-Roosevelt Hospital Center.

Adie Friedman, MD, and Carlos Benitez, MD, are radiology attendings at St. Luke’s-Roosevelt Hospital Center.

Sumit Talwar, MD, is a hematology oncology fellow at St. Luke’s-Roosevelt Hospital Center.

For more information:

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• Sprecher S. J Bone Miner Res. 2002;17:1929-1930.
• Vande Berg BC. Semin Musculoskelet Radiol. 2001;5:69-77.