In patients who are considered to be potentially curable after conventional imaging, F-FDG PET/CT can detect unsuspected sites of distant metastases (M1b) in a significant number of cases and thus contribute to the clinical decision-making process. PET/CT should be an integral part of the staging workup of patients with esophageal adenocarcinoma.

We report a case of oncogenic osteomalacia in which F-18 FDG PET imaging played a crucial role in detecting the occult neoplasm. A 39-year-old female patient presented with low backache and bilateral lower limb pain of 3-year duration. On evaluation, she was found to have hypophosphatemic osteomalacia and was referred for F-18 FDG PET scan because her initial clinical and radiologic evaluation failed to detect a tumor. F-18 FDG PET scan revealed a hypermetabolic focus in right popliteal fossa, which was correlated as a tumor in soft tissues of right popliteal fossa on magnetic resonance imaging. Following surgical excision of tumor, final histopathology revealed a benign phosphaturic mesenchymal tumor of mixed connective tissue origin. Postoperatively, her symptoms alleviated and serum phosphates normalized within 2 weeks. We suggest that F-18 FDG PET should be performed in such cases to localize occult neoplasm that may be otherwise missed on conventional radiologic imaging.

A 65-year-old man underwent FDG PET/CT for evaluation of vertebral lesions, radiologically suspected to be metastases. The scan showed hypermetabolism in D8 to D9 vertebrae, retroperitoneal lymph nodes, and both the lobes of prostate. Transrectal ultrasound-guided biopsy of prostate was performed with suspicion of prostate malignancy. The biopsy revealed caseating granulomatous lesions in prostate suggestive of tuberculosis. Post antitubercular treatment patient showed excellent clinical response. Possibility of infective pathologies mimicking malignancy should be kept in mind while evaluating hypermetabolic foci seen on PET/CT. Although rare, tuberculosis of prostate needs consideration in differential diagnosis of FDG-avid foci seen in prostate.

A 70-year-old man underwent Tc-methylene diphosphonate scintigraphy for staging of adenocarcinoma prostate. Scintigraphy revealed diffuse increased tracer uptake in skeletal system along with faint renal visualization, a pattern compatible with metastatic superscan. The scintigraphy also revealed increased radiotracer uptake in the body of the mandible-Lincoln sign or black beard sign. Radiological imaging revealed sclerotic lesions throughout the skeleton including the mandible, confirming widespread skeletal metastases. Lincoln sign is previously described in monostotic Paget disease of the mandible and in contiguous spread of oral malignancy. We describe this pattern in distant metastatic involvement from carcinoma prostate with coexistent superscan pattern.

Extramedullary hematopoiesis refers to the presence of hematopoietic elements in locations other than the bone marrow medullary space. It occurs as a compensatory mechanism to impaired hematopoiesis resulting from a variety of pathological conditions. Because of the hazards of biopsy of a highly vascular hematopoietic mass, it is desirable to establish the diagnosis noninvasively. We report a case where 18F-fluoro-3'deoxy-L-thymidine PET/CT and 99mTc-SC scintigraphy were used as a noninvasive modality to diagnose extramedullary hematopoiesis.