Locally aggressive and multifocal phosphaturic mesenchymal tumors: two unusual cases of tumor-induced osteomalacia.

Tumor-induced osteomalacia (TIO) has long been recognized as a clinical paraneoplastic syndrome. The identification of a unique histopathologic entity, the phosphaturic mesenchymal tumor (PMT), as a distinct etiology for TIO has been a more recent discovery. The majority of published cases describe a solitary, non-aggressive appearing soft tissue or osseous lesions in patients with osteomalacia; aggressive appearing or multifocal lesions appear to be exceedingly rare. These tumors characteristically secrete fibroblast growth factor 23 (FGF23). Elevated serum levels of FGF23 result in phosphate wasting and osteomalacia. In the majority of cases, laboratory abnormalities and clinical signs and symptoms of osteomalacia precede identification of the causative lesion by years. Following diagnosis, complete resection with wide margins to prevent local recurrence is most often curative. Imaging characteristics of PMT are diverse and remain incompletely defined, as the majority of previous publications are outside of the radiologic literature. We present multiple imaging modalities in two cases of patients with debilitating osteomalacia and unusual appearing PMTs: one with a locally aggressive lesion leading to pathologic fracture, the second presenting with exceedingly rare multifocal PMT.

Aplasia of the parotid glands with accessory parotid tissue.

Congenital absence of the parotid gland is a rare entity. Absence is most commonly unilateral, and is not associated with accessory glandular tissue. In the majority of reported cases, parotid gland aplasia is seen with craniofacial abnormalities or hypoplasia of other ectodermal structures, particularly the lacrimal glands. We present a 14-year-old male with bilateral parotid gland aplasia detected incidentally on MRI of the brain and then confirmed on neck CT. The studies also revealed accessory parotid tissue superficial to the left masseter muscle. There were no associated craniofacial abnormalities. The lacrimal glands and submandibular glands were normal.

Expectoration of an inferior vena cava filter strut.

Inferior vena cava (IVC) filter use is widespread in patients with venous thromboembolism (VTE) and temporary contraindication to anticoagulation, though timely removal is often not performed. We report the case of an expectoration of an IVC filter strut. Review of the patient's prior imaging confirmed an infrarenal Bard G2 filter with an absent strut, which was visualised in the left lung base. The strut was presumed to have embolised to a pulmonary artery branch and eroded into an adjacent bronchus. Subsequent fluoroscopically guided filter retrieval was successful. The incidence of IVC filter fractures increases with longer dwell times. Filter fragment embolisation has resulted in major adverse events, including sudden death and cardiac tamponade. Recent evidence has suggested that retrieval of IVC filters with prolonged dwell times is feasible and safe. This report brings awareness to the range of complications with indwelling IVC filters, and highlights the importance of timely removal.