The anatomical basis for preserving the blood supply to the parathyroids during thyroid surgery, and a review of current technologic advances.

BACKGROUND: Devascularization of the parathyroid glands is generally accepted as the most common mechanism for iatrogenic hypocalcemia, a frequently seen complication of both total and completion thyroidectomy procedures. Much has been written about iatrogenic hypoparathyroidism, but few papers have precisely delineated the arterial supply of the parathyroid glands and the common anatomical variations that may impact parathyroid preservation during thyroid surgery. METHODS: We offer an illustrated review and discussion of the only two anatomic studies published in the medical literature focusing on parathyroid vasculature. In addition, we examine current techniques of parathyroid identification, preservation, and classification. FINDINGS: A surgical technique that preserves the parathyroid arteries is vital to preserving the viability of the parathyroid gland(s) during thyroid surgery. In 1907, Halsted and Evans described a technique of ligating the distal branches of the thyroid arteries beyond the origin of the parathyroid arteries, a technique termed ultra-ligation. In 1982, Flament et al.. reported three distinct anatomical variations of the parathyroid arteries which place the parathyroid blood supply at risk for devascularization during thyroid surgery. Our review also highlights novel techniques that aid surgeons in identification and assessment of the parathyroid glands. CONCLUSIONS: Recognition of the variations of parathyroid anatomy and their potential to lead to devascularization aids thyroid surgeons in their pursuit of parathyroid preservation. An awareness of the variety of novel parathyroid identification and preservation techniques can assist surgeons to achieve this goal.

The Prevalence of Extranodal Extension in Papillary Thyroid Cancer Based on the Size of the Metastatic Node: Adverse Histologic Features Are Not Limited to Larger Lymph Nodes.

Extranodal extension (ENE) is a prognostic indicator of aggressiveness for papillary thyroid cancer (PTC). The association between the size of metastatic nodes and the prevalence of ENE has not been previously explored. However, there is a common belief that small lymph nodes with metastatic disease do not significantly impact patient outcome. This study investigates the relationship between the prevalence of ENE and the size of a positive lymph node. Linear dimensions and malignant histological characteristics of 979 metastatic lymph nodes from 152 thyroid cancer patients were retrospectively analyzed. Data was analyzed using chi-square tests and multilevel logistic regression modeling. ENE was present in 144 of 979 lymph nodes; the sizes of the involved lymph nodes ranged from 0.9 to 44 mm. ENE was identified in 7.8% of lymph nodes measuring ≤ 5 mm, 18.9% between 6 and 10 mm, 23.1% between 11 and 15 mm, 25.0% between 16 and 20 mm, and 14.0% between 21 and 25 mm in size. The association between node size and ENE status was significant (odds ratio (OR) = 1.07, confidence interval (CI) = [1.04, 1.11]). The size of the metastatic focus directly correlated with ENE (OR = 1.07, 95% CI = [1.07, 1.14], p value < 0.001). Increasing lymph node size increases the likelihood of ENE for metastatic PTC. Importantly, small positive lymph nodes can also harbor ENE to a significant extent. Further studies are required to determine the clinical and prognostic significance of lymph node size and the presence of ENE.

Pathologic Reporting of Tall-Cell Variant of Papillary Thyroid Cancer: Have We Reached a Consensus?

BACKGROUND: Tall-cell variant (TCV) is widely believed to be a more aggressive subtype of papillary thyroid carcinoma (PTC). Despite the significance of TCV with respect to risk stratification and therapeutic decision making, its diagnosis is subject to inter-observer variability. This study aimed to determine the level of agreement among expert pathologists in the identification and reporting of TCV. METHODS: Seventeen surgical resections for thyroid cancer containing the diagnostic term "tall cell" in their pathology reports and 22 cases diagnosed as classical PTC were selected. Cases were digitalized, and 14 expert pathologists reviewed the scanned slides blinded to the original interpretation. Each pathologist designated each case as TCV or not and answered multiple questions about diagnostic histopathologic features of TCV. RESULTS: The overall strength of agreement for identifying TCV was fair (Fleiss kappa 0.34), and the proportion of observed agreement was 0.70. Of 22 cases originally diagnosed as PTC classical variant, 15 (68%) were reclassified as TCV by at least one expert pathologist. It was noted that four different definitions for TCV were used by the participants based on various combinations of cell height to width (H:W) ratio and the percentage of tumor cells showing that specific ratio. All pathologists agreed that the diagnosis of TCV does not rely solely on a specific H:W ratio. CONCLUSIONS: Pathologic reporting of TCV varies among pathologists. This disagreement is a result of the lack of unanimous diagnostic criteria and variation in individual pathologists' interpretations. These discrepancies lead to over- and under-diagnosis of TCV, which has significant implications in patient management. It is imperative to understand this variability in diagnosis TCV as it relates to risk stratification and interpretation of clinical studies related to this histologic subtype of PTC. Further studies are needed to reach consensus on the diagnostic criteria of TCV.

Intermittent facial spasms as the presenting sign of a recurrent pleomorphic adenoma.

The intimate anatomical relationship of the facial nerve to the parotid parenchyma has a significant influence on the presenting signs and symptoms, diagnosis and treatment of parotid neoplasms. However, to our knowledge, hyperactivity of this nerve, presenting as facial spasm, has never been described as the presenting sign or symptom of a parotid malignancy. We report a case of carcinoma arising in a recurrent pleomorphic adenoma of the left parotid gland (i.e., carcinoma ex pleomorphic adenoma) that presented with hemifacial spasms. We outline the differential diagnosis of hemifacial spasm as well as a proposed pathophysiology. Facial paralysis, lymph node enlargement, skin involvement, and pain have all been associated with parotid malignancies. To date the development of facial spasm has not been reported with parotid malignancies. The most common etiologies for hemifacial spasm are vascular compression of the ipsilateral facial nerve at the cerebellopontine angle (termed primary or idiopathic) (62%), hereditary (2%), secondary to Bell's palsy or facial nerve injury (17%), and hemifacial spasm mimickers (psychogenic, tics, dystonia, myoclonus, myokymia, myorthythmia, and hemimasticatory spasm) (17%). Hemifacial spasm has not been reported in association with a malignant parotid tumor but must be considered in the differential diagnosis of this presenting symptom.

Influence of previous treatment of oral squamous cell carcinoma on the geographic distribution of recurrent neck metastases: A case series of unusual level 4 metastases.

BACKGROUND: Cervical node management is vital for the successful treatment of oral squamous cell carcinoma (OSCC). Lymphatic spread from intra-oral malignancies usually follows a predictable path. We report on two patients with isolated level 4 recurrence following previous treatment for OSCC. METHODS: Single institutional case series. RESULTS: Two patients, initially N0, treated by surgery and ipsilateral neck dissection, presented with recurrent OSCC. One patient received adjuvant radiotherapy. Both patients developed recurrent/new disease at 7years and and 22months, respectively, and had salvage surgery, one had adjuvant radiation therapy. Both, subsequently, presented again at 3 and 12months with isolated, ipsilateral level 4 metastases. CONCLUSION: These two patients presented with delayed skip metastases which defies normal drainage patterns. The experience with these patients and a review of the literature raises the question of addressing the treatment of level 4 lymph nodes in recurrent OSCC due to altered drainage.

The importance of recognizing a cervical origin of the right subclavian artery.

Cervical origin of the right subclavian artery is rare and is associated with DiGeorge syndrome. During total thyroidectomy and right lateral neck dissection for metastatic thyroid cancer in a 26-year-old female, the right subclavian artery was found to be cervical in origin. This was identifiable on preoperative computerized tomography. Screening for DiGeorge syndrome and other cardiovascular abnormalities in this patient was negative. However, all reported cases of this right subclavian artery anomaly tested positive for DiGeorge syndrome. Cervical origin of the right subclavian artery may present in the absence of DiGeorge syndrome. Laryngoscope, 126:2497-2499, 2016.