No abstract

Double-phase scintigraphy using Tc-99m sestamibi MIBI is the study of choice for detecting parathyroid adenoma in patients with primary hyperparathyroidism. However, before parathyroid imaging, these patients may uncommonly present with multiple osteolytic lesions and bone scan findings consistent with metastatic disease. By excluding malignancy, the diagnosis of osteitis fibrosa cystica and parathyroid adenoma may subsequently be confirmed. The authors describe the case of an elderly patient who presented with imaging findings initially masquerading as metastatic disease. When parathyroid adenoma was finally diagnosed with Tc-99m MIBI imaging, radiopharmaceutical uptake was also noted within several brown tumors, including clinically significant brown tumors of the left lower extremity, a finding that has not been previously reported.

We report on a 19-year-old male diagnosed with multiple pheochromocytomas after an I-123 metaiodobenzylguanidine (MIBG) scan. Multiple imaging was obtained because of concern for von Hippel-Lindau disease (VHL) after bilateral retinal angiomas were discovered on ophthalmologic consultation as a follow-up from the Emergency Department. Computed tomography (CT) and magnetic resonance imaging (MRI) were able to localize the adrenal and extra-adrenal tumors; however, accurate differentiation between pheochromocytomas and other adrenal tumors was not possible. I-123 MIBG is the test of choice for evaluating functionality and location of pheochromocytomas because of its high sensitivity and specificity. I-123 MIBG was performed before surgery to confirm that the lesions were indeed pheochromocytomas and also to rule out metastatic disease. He was started on alpha- and beta-blocker medication for at least 3 weeks, followed by surgery. The postoperative period was uneventful. DNA testing was performed and revealed mutations in the VHL gene previously reported to be associated with von Hippel-Lindau syndrome type II and genetic counseling was recommended. He was presented in urology tumor board conference with recommendations for follow-up CT and laboratory tests after 3 months. Otherwise, the patient is doing well and asymptomatic at this time.

The authors report two cases of round atelectasis that showed increased accumulation of technetium (Tc) 99m depreotide on planar and single photon emission computed tomographic scintigraphy. It should be considered that round atelectasis is a potential nonmalignant cause for positive 99mTc depreotide scintigraphy.

The literature is replete with cases of Tc-99m bone imaging agent uptake in pleural effusions. Far rarer is the report of photopenia in a pleural effusion. In this case of malignant mesothelioma, we describe a unique case of unilateral hemithoracic photopenia from a pleural effusion with concomitant uptake in the contralateral lung resulting from calcified pleural plaques. Although initially perplexing clinically, this case can be readily explained with an understanding of basic physiological principles.