Technetium-99m sestamibi single-photon emission computed tomography/computed tomography (99mTc-sestamibi SPECT/CT) is a mainstay of the pre-operative localization of parathyroid lesions. We report here the case of a 30 year-old woman with a fortuitously discovered 2 cm cervical mass for which a parathyroid origin was originally suspected due to its retro-thyroidal localization and a personal history of nephrolithiasis. Normal serum calcium and parathyroid hormone (PTH) levels excluded primary hyperparathyroidism, raising suspicion of a non-functional parathyroid adenoma, and SPECT/CT imaging showed that the mass was 99mTc-sestamibi-avid. Fine-needle aspiration (FNA) was performed; cytology was non-diagnostic but the needle washout was negative for thyroglobulin, calcitonin and PTH, arguing against a thyroidal or parathyroidal origin of the mass. Core needle biopsy revealed a schwannoma, ostensibly originating from the recurrent laryngeal nerve; upon surgical resection, it was finally found to arise from the esophageal submucosa. This case illustrates the fact that endocrinologists, radiologists, nuclear medicine, head and neck, and other specialists investigating patients with cervical masses should be aware that schwannomas need to be considered in the differential diagnosis of focal 99mTc-sestamibi uptake in the neck region.

BACKGROUND: Primary aortoduodenal fistula is a rare cause of gastrointestinal (GI) bleeding consisting of abnormal channels between the aorta and GI tract without previous vascular intervention that results in massive intraluminal hemorrhage.
METHODS: A 67-year-old man was hospitalized for coffee ground vomiting, tarry stools, and colic abdominal pain. He was repeatedly admitted for active GI bleeding and hypovolemic shock. Intermittent and spontaneously stopped bleeders were undetectable on multiple GI endoscopy, angiography, computed tomography angiography (CTA), capsule endoscopy, and 99mTc-labeled red blood cell (RBC) scans. The patient received supportive treatment and was discharged without signs of rebleeding. Thereafter, he was re-admitted for bleeder identification. Repeated CTA after a bleed revealed a small aortic aneurysm at the renal level contacting the fourth portion of the duodenum. A 99mTc-labeled RBC single-photon emission CT (SPECT)/CT scan performed during bleeding symptoms revealed active bleeding at the duodenal level. According to his clinical symptoms (intermittent massive GI bleeding with hypovolemic shock, dizziness, dark red stool, and bloody vomitus) and the abdominal CTA and 99mTc-labeled RBC SPECT/CT results, we suspected a small aneurysm and an aortoduodenal fistula. Subsequent duodenal excision and duodenojejunal anastomosis were performed. A 7-mm saccular aneurysm arising from the anterior wall of the abdominal aorta near the left renal artery was identified. Percutaneous intravascular stenting of the abdominal aorta was performed and his symptoms improved.
CONCLUSIONS: Our findings suggest that 99mTc-labeled RBC SPECT/CT scanning can aid the diagnosis of a rare cause of active GI bleeding.

Breast cancer liver metastasis (BCLM) is considered to occur by hematogenous spread of primary breast cancer cells. We herein present a case of lymphatic BCLM that was confirmed by preoperative imaging for sentinel lymph node biopsy (SLNB). A woman in her early 70s was diagnosed with clinical stage T2N0M0 invasive lobular cancer of the left breast. She underwent mastectomy with SLNB. Preoperative lymphoscintigraphy showed intense accumulation of isotope in the upper abdomen, corresponding to segment IV of the liver on single-photon emission computed tomography/computed tomography (SPECT/CT). However, no abnormalities were detected on magnetic resonance imaging. At 2.5 years postoperatively, the patient\'s serum CA15-3 concentration was elevated, and positron emission tomography/computed tomography (PET/CT) showed a solitary liver metastasis. The PET/CT findings were similar to the SPECT/CT findings obtained 2.5 years earlier, indicating that the BCLM had developed lymphatically. To the best of our knowledge, this is the first case report of lymphatic BCLM proven by imaging examination.

Megaprosthesis is used to restore the form and function of massive skeletal defects, but it is accompanied by risks of failure, mainly due to perimegaprosthetic infection (PMI). In practice, the diagnosis of infected megaprosthesis among patients with a high index of clinical suspicion, elevated serological markers, and multiple negative or inconclusive imaging can be very challenging and poses a diagnostic conundrum to many orthopaedic surgeons. We present the case of a symptomatic 26-year-old female with large B-cell lymphoma who developed cellulitis with suspected complication of PMI 15 months post-implantation. The combination of advanced nuclear medicine imaging strategies, i.e., 99mTc-besilesomab/99mTc-sulfur colloid scintigraphy with hybrid single-photon emission computed tomography/computed tomography (SPECT/CT) scanning helps to characterise and delineate both infections. Invasive procedures such as joint aspiration and biopsy were avoided, and the patient was successfully treated with antibiotics. Hence, we report a case where advanced imaging modalities were decisive in the investigation of PMI.

We describe the lymphoscintigraphy findings of a 25-year-old female patient who was undergoing presurgical workup for lymphangiomas of the vulva. She had a history of treatment for disseminated tuberculosis 6 years back and presented with herpetiform oozing vesicles in the external genitalia. Single-photon emission computed tomography/computed tomography (SPECT/CT) confirmed cutaneous tracer accumulation in the vulval lesions and demonstrated the presence of densely calcified inguinal nodes secondary to healed tuberculosis as the etiology of secondary lymphangioma.

A 72-year-old male with a history of prostate cancer and high prostate specific antigen levels underwent 99mtechnetium-methylene diphosphonate (99mTc-MDP) single-photon emission computed tomography/computed tomography (SPECT/CT), to identify bone metastasis. The patient possessed no previous history of serious illnesses or surgical procedures and no family history of malignancies. A whole-body CT scan revealed an intense MDP uptake in the right inguinal region on the anterior view, but not in the posterior view, which was suspected to be a metastatic lesion. However, there was no evidence of bone metastasis on the CT scan. In addition, an increased 99mTc-MDP uptake was indicated on the SPECT images in the right inguinal region, which appeared to be separate from the main bladder activity. CT images of the pelvis revealed an inferior tongue-like extension of the bladder into the right inguinal region. Fused SPECT/CT axial images indicated the circular accumulation of the 99mTc-MDP in the medial right groin, with well-defined walls that connected the accumulation to the bladder. The final diagnosis was a bladder hernia (T2N0M0), which may have been responsible for the misdiagnosis of bone metastasis due to the use of radiopharmaceuticals (99mTc-MDP) that were mainly excreted through urination. Considering the comprehensive situation of the patient, radical prostatectomy was performed. The bladder hernia was subsequently monitored by follow-up examination every 3 months, and remains alive and under follow-up to date.

We present a case report where Tc-99m sulfur colloid single-photon emission computed tomography (SPECT)/computed tomography (CT) scan was useful in characterizing a soft tissue abdominal mass and helped with patient management. A 63-year-old male with no previous history of trauma had an incidental finding of a soft tissue nodule adjacent to the splenic hilum, unchanged in size over 4 months and with similar enhancing features as the spleen. A Tc-99m sulfur colloid SPECT/CT scan was performed to determine the nature of the nodule. It showed no uptake of tracer within this mass, therefore excluding splenic tissue. This prompted subsequent investigations and this tissue was found to represent a pancreatic neuroendocrine tumor, which was excised.