Cervical lymph node sarcoidosis mimicking a parathyroid adenoma: a clinical case

Sarcoidosis, the master mimicker

Sarcoidosis is an idiopathic multisystem disorder characterized by noncaseating granulomas. The article focuses on the typical imaging manifestations of sarcoid and the common differentials that need to be included when appropriate. Mistaking a sarcoid-mimicking disease for sarcoid can result in increased patient morbidity and mortality. The pulmonary system is the most common system involved and is typically the best understood by the radiologist, however a deeper knowledge of the pulmonary findings and features of sarcoid in other organ systems is critical. There is a myriad of sarcoid imaging manifestations that can involve every organ system. Often a confidant diagnosis of sarcoid can be made, however a broad differential may need to be considered- differential diagnoses include primary neoplasm, metastatic disease, infectious, and inflammatory etiologies. Radiologist familiarity with the multimodality multisystem imaging findings of sarcoid can help guide clinical management and optimize patient care.

Retropharyngeal ectopic parathyroid adenoma versus lymph node: Problem solving with CT neck angiogram

A 66-year-old female underwent preoperative evaluation for primary hyperparathyroidism. Ultrasound (US) neck and technetium (Tc)-99m-sestamibi planar scintigraphy were negative, but single photon emission computed tomography/computed tomography (SPECT/CT) demonstrated a tracer-avid retropharyngeal nodule compatible with parathyroid adenoma (PTA). A retrospective review of CT neck angiogram (CTA) and neck magnetic resonance imaging (MRI) performed 4 months earlier for stroke evaluation revealed arterial phase hyperenhancing retropharyngeal tissue, which had been dismissed as a nonpathological lymph node. “Polar vessel sign” seen in two-thirds of PTA was also present on retrospective review of the CTA. The concordant findings between SPECT/CT and CTA were indicative of a solitary undescended ectopic PTA in the retropharyngeal space, an uncommon location. A successful surgical cure was achieved after minimally invasive parathyroidectomy. This case highlights the retropharyngeal space as an important ectopic site of PTA, limitation of US, and Tc-99m-sestamibi planar scintigraphy in identifying retropharyngeal PTA. We also discuss the role of CT and MRI and the challenge in differentiating retropharyngeal PTA from a lymph node.

Hybrid-fusion SPECT/CT systems in parathyroid adenoma: Technological improvements and added clinical diagnostic value

Nuclear medicine traditionally employs planar and single photon emission computed tomography (SPECT) imaging techniques to depict the biodistribution of radiotracers for the diagnostic investigation of a range of disorders of endocrine gland function. The usefulness of combining functional information with anatomy derived from computed tomography (CT), magnetic resonance imaging (MRI), and high resolution ultrasound (US), has long been appreciated, either using visual side-by-side correlation, or software-based co-registration. The emergence of hybrid SPECT/CT camera technology now allows the simultaneous acquisition of combined multi-modality imaging, with seamless fusion of 3D volume datasets. Thus, it is not surprising that there is growing literature describing the many advantages that contemporary SPECT/CT technology brings to radionuclide investigation of endocrine disorders, showing potential advantages for the pre-operative locating of the parathyroid adenoma using a minimally invasive surgical approach, especially in the presence of ectopic glands and in multiglandular disease. In conclusion, hybrid SPECT/CT imaging has become an essential tool to ensure the most accurate diagnostic in the management of patients with hyperparathyroidism.

Endocrine radionuclide scintigraphy with fusion single photon emission computed tomography/computed tomography

AIM: To review the benefits of single photon emission computed tomography (SPECT)/computed tomography (CT) hybrid imaging for diagnosis of various endocrine disorders.

METHODS: We performed MEDLINE and PubMed searches using the terms: “SPECT/CT”; “functional anatomic mapping”; “transmission emission tomography”; “parathyroid adenoma”; “thyroid cancer”; “neuroendocrine tumor”; “adrenal”; “pheochromocytoma”; “paraganglioma”; in order to identify relevant articles published in English during the years 2003 to 2015. Reference lists from the articles were reviewed to identify additional pertinent articles. Retrieved manuscripts (case reports, reviews, meta-analyses and abstracts) concerning the application of SPECT/CT to endocrine imaging were analyzed to provide a descriptive synthesis of the utility of this technology.

RESULTS: The emergence of hybrid SPECT/CT camera technology now allows simultaneous acquisition of combined multi-modality imaging, with seamless fusion of three-dimensional volume datasets. The usefulness of combining functional information to depict the bio-distribution of radiotracers that map cellular processes of the endocrine system and tumors of endocrine origin, with anatomy derived from CT, has improved the diagnostic capability of scintigraphy for a range of disorders of endocrine gland function. The literature describes benefits of SPECT/CT for ^99mTc-sestamibi parathyroid scintigraphy and ^99mTc-pertechnetate thyroid scintigraphy, ¹²³I- or ¹³¹I-radioiodine for staging of differentiated thyroid carcinoma, ¹¹¹In- and ^99mTc- labeled somatostatin receptor analogues for detection of neuroendocrine tumors, ¹³¹I-norcholesterol (NP-59) scans for assessment of adrenal cortical hyperfunction, and ¹²³I- or ¹³¹I-metaiodobenzylguanidine imaging for evaluation of pheochromocytoma and paraganglioma.

CONCLUSION: SPECT/CT exploits the synergism between the functional information from radiopharmaceutical imaging and anatomy from CT, translating to improved diagnostic accuracy and meaningful impact on patient care.

Feasibility of unilateral parathyroidectomy in patients with primary hyperparathyroidism and negative or discordant localization studies

The purpose of this study was to examine the feasibility of unilateral parathyroidectomy in patients with primary hyperparathyroidism and negative or discordant localization studies. We included in our study 72 patients with preoperative diagnosis of primary hyperparathyroidism who had negative or discordant preoperative studies. In 66 patients, studies were discordant while in six were both negative. In 40 (55.6 %) patients initial approach was a bilateral exploration. In 32 cases (44.4 %) initial surgery was a unilateral exploration: in 26 conservative approach was successful, in six mini-invasive surgery failed and a bilateral exploration was necessary due to IOPTH negative test (five cases) or to the impossibility to find a pathological gland during exploration (one case). Intra-operative PTH test showed a sensitivity of 93.2 %, a specificity of 92.3 %, and an accuracy of 93.1 %. Multiple gland disease was found in 8 (11.1 %) patients (two double adenoma and six multiple gland hyperplasia). Mean operative time was lower in unilateral exploration group (87.9 ± 43.8 min). Comparing unilateral surgery in negative or discordant studies with 77 consecutive patients who underwent focused surgery with positive and concordant studies, conversion to bilateral exploration rate was statistically significantly higher in the first group (15.6 %). We believe that unilateral parathyroidectomy can be safely performed also in patients with discordant localization studies with a high cure rate; in these cases, however, the use of intra-operative PTH is absolutely necessary. We suggest the need for referral of these patients to high-volume medical centers for thyroid and parathyroid surgery.

Sarcoidosis of the head and neck

Sarcoidosis is a complex disorder that often times involves the head and neck. Despite the presence of strong clinical evidence, tissue diagnosis and imaging is needed for confirmation of the disease. Although typically managed medically, when found in the sinonasal tract or intracranially, it may necessitate the intervention of a rhinologist-skull base surgeon. This article seeks to provide a comprehensive review of head and neck sarcoidosis, as this fascinating disorder often poses a diagnostic and therapeutic challenge. A brief discussion of surgical treatment for pituitary lesions is also provided. Articles from 1997 to 2013 were selected and reviewed by three researchers utilizing the most recent literature regarding sarcoidosis in the head and neck. PubMed searches were conducted using search terms such as "sarcoidosis", "neurosarcoid", and "extra-pulmonary sarcoid", among many others. A large collection of articles was generated and reviewed by the team of authors, and appropriate information was extracted to compose a thorough and expansive review of the subject. 10-15 % of patients with sarcoidosis have head and neck manifestations. Sinonasal and pituitary sarcoidosis presents a diagnostic challenge owing to its non-specific symptoms. Although systemic steroid therapy is often the first time treatment, endoscopic surgery is commonly used to treat advanced pituitary sarcoidosis refractory to medical management. As tissue diagnosis and imaging is key, a multi-disciplinary team approach is advantageous. Our study collates the available literature on head and neck sarcoidosis to provide a comprehensive review of the subject. This provides helpful information to guide all practitioners involved in the care of these challenging patients, namely pathologists, radiologists, otolaryngologists, and skull base surgeons, in the workup and management of head and neck sarcoidosis.