Negative correlation was found between cellularity and ADC metrics of common pediatric cerebellar tumors. Although ADC metrics are useful in the preoperative diagnosis of common pediatric cerebellar tumors and this utility is generally attributed to differences in cellularity of tumors, tumor cellularity may not be the sole determinant of the differences in diffusivity.

Hypophosphatemia with osteomalacia may be due to a neoplasm that produces fibroblast growth factor 23 (FGF-23), which inhibits phosphate reabsorption in the kidneys. Most of these tumors occur in bone or soft tissue and occasionally in the head, although intracranial occurrence is very rare. This report describes a tumor that caused hypophosphatemia and osteomalacia and was located entirely in the right anterior cranial fossa. Radiologically, the tumor resembled a meningioma; histologically, it was a low-grade phosphaturic mesenchymal tumor, mixed connective tissue variant (PMTMCT). After gross-total resection, the patient's symptoms abated and laboratory values normalized. The authors also studied another PMTMCT initially diagnosed as a hemangiopericytoma that involved the left anterior cranial fossa and ethmoid sinus, and reviewed reports of 6 other intracranial tumors that induced osteomalacia, 3 entirely in the anterior cranial fossa, 2 involving the anterior cranial fossa and ethmoid sinus, and 1 in the cavernous sinus. In older children or adults who have hypophosphatemia with osteomalacia and no personal or family history of metabolic, renal, or malabsorptive disease, a neoplasm should be suspected and an imaging workup that includes the brain is warranted, with particular attention to the anterior cranial fossa. Additionally, because there are some overlapping histological features between PMTMCTs and hemangiopericytomas, it may be helpful to assess tumoral FGF-23 expression by reverse transcriptase polymerase chain reaction or immunohistochemical analysis in patients with oncogenic osteomalacia from an intracranial tumor diagnosed as, or resembling, hemangiopericytoma.

BACKGROUND AND PURPOSE: Pleomorphic xanthoastrocytomas are rare astrocytic neoplasms of childhood and young adulthood. The purpose of this retrospective review was to evaluate MR imaging features of pediatric pleomorphic xanthoastrocytomas with an emphasis on diffusion MR imaging.

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Increasingly, positron emission tomography/computed tomography (PET/CT) is being used as a tumor surveillance modality for multiple tumor types. A 73-year-old postmenopausal female with stage IV nonsmall cell lung cancer presented after a PET/CT demonstrated focal uptake in the superior and lateral aspects of the uterus. The patient reported a history of intermittent postmenopausal bleeding and an endometrial biopsy documented uterine carcinosarcoma. Postoperative pathologic review and immunohistochemical staining with thyroid transcription factor-1 revealed metastatic adenocarcinoma consistent with her lung primary in her uterus and adnexa. Our case represents a rare occurrence in which lung cancer has metastasized to multiple female pelvic organs. Increasing use of PET/CT may lead to the discovery of occult metastases masquerading as a second primary malignancy.