Parathyroid Carcinoma - A Malignant Cause of Metabolic Skeletal Super Scan on Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography.

Excessive abnormal tracer uptake in active tracer avid organ(s) with the suppression of physiological background tracer distribution is termed as super scan. Herein, we present an 18F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET/CT), where the metabolic pattern of skeletal super scan with coexistent parathyroid tumor was seen giving rise to the suspicion of primary hyperparathyroidism. It was subsequently diagnosed as a case of parathyroid carcinoma. Very high levels of serum parathormone in parathyroid carcinoma lead to accelerated bone turn over resulting in metabolic skeletal superscan in FDG-PET/CT which is seldom observed in parathyroid adenoma.

Advantage of Hybrid 18F-Fluoride Positron Emission Tomography/Computed Tomography to Diagnose Malignant Rib Invasion by Pleural Metastasis in a Background of Reactive Periostitis.

Diffuse osteoblastic activity in the ribs on bone scan is seen in association with pleural thickening. Irrespective of the pleural pathology, this represents benign finding caused by pleural hyperemia or reactive periostitis, with preserved cortical integrity. However, malignant involvement of the ribs can occur by local invasion of pleural malignancy causing cortical lysis. Herein, we describe the 18F-fluoride positron emission tomography/computed tomography findings of reactive periostitis of the ribs in pleural metastasis and emphasize the advantage of hybrid imaging in detecting local malignant tumor invasion superimposed in such condition.

Obstructive Jaundice: An Unusual Presentation of Neuroendocrine Differentiation in Prostatic Adenocarcinoma.

An elderly male on androgen deprivation therapy for prostatic adenocarcinoma presented with obstructive jaundice. Since biopsy from the head of the pancreas showed neuroendocrine carcinoma (NEC), he was diagnosed with second primary pancreatic NEC. Ga-68 DOTANOC positron emission tomography/computed tomography (PET/CT) done subsequently showed enlarged mildly DOTANOC-avid retroperitoneal nodes infiltrating the pancreas. These nodes were found to be progression of prostate-specific membrane antigen (PSMA) nonavid retroperitoneal nodes visualized in his Ga-68 PSMA PET/CT performed at another institution before 4 months, when there was no lesion in the pancreas. This observation revised the diagnosis from second primary pancreatic NEC to progression of neuroendocrine differentiation in preexisting prostatic adenocarcinoma.

Delayed 68Ga-PSMA PET/CT Image-Guided Biopsy for Low-Grade Adenocarcinoma in Benign Prostatic Hyperplasia.

ABSTRACT: Image-guided biopsy of prostate with multiparametric MRI is being adopted in the workup of prostate adenocarcinoma (PAC). 68Ga-PSMA PET/CT-guided biopsy has also been shown to be equally sensitive in the evaluation of higher-grade tumors with increased PSMA expression. The sensitivity of 68Ga-PSMA PET/CT, however, reduces with lesser PSMA expression in low-grade PAC. Herein, we demonstrate a case where delayed 68Ga-PSMA PET/CT imaging helped in detecting low-grade PAC in BPH.

De Novo Presentation of Sarcoidosis on Restaging FDG PET/CT in Rectal Carcinoma With Self-resolution.

Sarcoidosis is a systemic disorder of unknown etiology characterized by development of noncaseating granulomas in more than 1 organ system. Development of sarcoidosis during or immediately after chemotherapy and immunotherapy is not uncommon. We present a 61-year-old woman in whom restaging F-FDG PET/CT detected asymptomatic sarcoidosis after neoadjuvant chemoradiotherapy for carcinoma rectum, which resolved spontaneously by the end of adjuvant chemotherapy with no specific treatment. Recognition of anatomic-metabolic pattern of sarcoidosis could prevent erroneous upstaging of the primary malignancy during restaging PET/CT following chemotherapy, and such lesions may show self-resolution.