Symptomatic Oppenheimer ossicle: a rare mimic of pars interarticularis fracture.

We report a case of symptomatic Oppenheimer ossicle in an 18-year-old male who presented with back pain. L5 pars interarticularis defect was suspected on initial lumbar spine radiographs. A subsequent technetium99m-methylene diphosphonate (Tc99m-MDP) bone scintigraphy with single-photon emission computed tomography/computed tomography (SPECT/CT) revealed focal radiotracer uptake in an Oppenheimer ossicle in L2 vertebra. CT was negative for pars defect. Oppenheimer ossicle is a developmental variant resulting from an unfused accessory ossification center at the tip of the articular process. It is important to recognize this entity as a rare cause of low back pain. Focal tracer uptake can mimic changes from pars interarticularis defect on planar and SPECT images. SPECT/CT helps to resolve both entities. To our knowledge, this is also the first report in English literature describing a symptomatic Oppenheimer ossicle on a bone scan.

Abdominal Pain and Intermittent Fevers in a 16-Year-Old Girl.

A 16-year-old girl presented to the emergency department with intermittent fevers and worsening abdominal pain of 5 weeks duration. She had a history of travel to a less developed country and exposure to possible infectious diseases. Abdominal imaging and blood tests revealed diffuse mesenteric lymphadenopathy, elevated transaminases, and elevation of inflammatory markers. Gastroesophageal and colon endoscopies revealed gastric ulcers, and the patient was discharged with a presumptive diagnosis of systemic juvenile idiopathic arthritis given the lymphadenopathy seen on imaging, serositis, sacroiliac joint stiffness noted on physical examination, and pain relief with celecoxib. She presented again 4 days later with worsening abdominal tenderness, elevated transaminases, and new-onset abdominal distention. Tissue biopsy yielded the diagnosis and directed appropriate treatment.

Pediatric hepatic rhabdoid tumor: A rare cause of abdominal mass in children.

Pediatric hepatic rhabdoid tumors are rare tumors of the liver, with few cases reported in the literature. These aggressive tumors can be difficult to differentiate from hepatoblastomas on imaging alone, and surgical biopsy combined with special immunohistochemical stains can assist in differentiating these 2 tumor types. We present a case of hepatic rhabdoid tumor in a 7-month-old female infant, which was originally thought to be a hepatoblastoma; however, using BAF47 staining for INI-1 we were able to diagnose a rhabdoid tumor and affect the patient's medical oncologic therapy. Earlier detection and a better understanding of the imaging features of hepatic rhabdoid tumor may aid in improved patient management and treatment planning.

Unenhanced MRI as an Alternative to 99mTc-Labeled Dimercaptosuccinic Acid Scintigraphy in the Detection of Pediatric Renal Scarring.

OBJECTIVE: The purpose of this study was to determine whether unenhanced MRI without sedation is a feasible substitute for dimercaptosuccinic acid (DMSA) scintigraphy in the detection of renal scars in pediatric patients. SUBJECTS AND METHODS: Patients scheduled for 99mTc-labeled DMSA scintigraphy for assessment of possible renal scars were recruited to undergo unenhanced MRI (free-breathing fat-suppressed T2-weighted single-shot turbo spin-echo and T1-weighted gradient-echo imaging, 13 minutes' total imaging time). Scintigraphic and MRI studies were evaluated by two independent blinded specialty-based radiologists. For each imaging examination, readers identified scars in upper, middle, and lower kidney zones and rated their diagnostic confidence and the quality of each study. The scintigraphic readers' consensus score opinion for the presence of scars was considered the reference standard. RESULTS: DMSA scintigraphy showed scarring in 19 of the 78 (24.4%) evaluated zones and MRI in 18 of the 78 (23.1%). The two MRI readers found mean sensitivities of 94.7% and 89.5%, identical specificities of 100%, and diagnostic accuracies of 98.7% and 97.4%. Interobserver agreement was 98.7% for MRI and 92.3% for DMSA scintigraphy. The MRI readers were significantly more confident in determining the absence rather than the presence of scars (p = 0.02). MRI readers were more likely to rate study quality as excellent (84.6%) than were the scintigraphic readers (57.7%) (p = 0.024). CONCLUSION: Unenhanced MRI has excellent sensitivity, specificity, diagnostic accuracy, and interobserver agreement for detecting renal scars in older children who do not need sedation. It may serve as a substitute modality, especially when DMSA is not available.

Gestational Primary Hyperparathyroidism Due to Ectopic Parathyroid Adenoma: Case Report and Literature Review.

Gestational primary hyperparathyroidism (GPHPT) is a rare condition with fewer than 200 cases reported. We present the case of a 21-year-old woman who presented at 10 weeks' gestation with severe hypercalcemia. Laboratory investigation was consistent with primary hyperparathyroidism. Neck ultrasound did not reveal any parathyroid enlargement. Due to the persistence of severe hypercalcemia, she was treated with 4 weeks of cinacalcet therapy, which was poorly tolerated due to nausea and vomiting. At 14 weeks' gestation, she underwent neck exploration with right lower, left upper, and partial right upper parathyroid gland excision. Intra- and postoperative parathyroid hormone (PTH) and calcium levels remained elevated. After a thorough discussion of risks/benefits, the patient requested further treatment. A parathyroid sestamibi scan (PSS) revealed an ectopic adenoma in the left mediastinum. The adenoma was removed via video-assisted thorascopic parathyroidectomy with intraoperative PTH declining to nearly undetectable levels. She ultimately delivered a physically and developmentally normal infant at 37 weeks' gestation. Appropriate treatment of severe GPHPT may prevent the maternal and fetal complications of hypercalcemia. This case, in which cinacalcet therapy and PSS were used, adds to the body of literature regarding treatment of severe GPHPT.