78-year-old male underwent radical prostatectomy six years prior to demise because of cancer of the prostate. (Specimen from autopsy. Section of a lumbar vertebra is shown).
- The bone is infiltrated by an adenocarcinoma consisting of small, well formed glands, arranged back-to-back with hardly any intervening stroma. The glands are lined by a uniform layer of cuboidal cells exhibiting slightly enlarged quite monomorphic hyperchromatic nuclei. In some instances, distinct nucleoli are visible. Few mitotic figures are present. (Of note, the tumor glands are smaller than the typical glands of the prostate).
- In between glands, a high number of newly formed bone spicules are present (osteoblastic metastasis). The latter form unorganized net-like structures, surrounding different sized marrow spaces which are packed with tumor glands.
- The cytoplasm of the tumor cells stains positive for prostate-specific antigen (PSA), allowing identification of the tissue of origin of the malignant glands.
Osteoblastic metastases are typically observed in cancer of the prostate. The X-ray correlate is the increased radiopacity of the sclerotic bone lesions.