Parathyroid Carcinoma: Report of Nine Cases from a University Hospital in Sao Paulo, Brazil

Presentation Number: MON 302
Date of Presentation: April 3rd, 2017

Alessandra Raphael Novelli*, Adriano Namo Cury, Nilza Maria Scalissi and Manuela GM Rocha-Braz
Irmandade da Santa Casa de Misericordia de Sao Paulo, Sao Paulo, Brazil

Abstract

Parathyroid carcinoma (PC) represents less than 1% of cases of primary hyperparathyroidism and is one of the rarest known malignancies. When hormonally functional (more than 90% of cases), clinical presentation is mainly due to severe hypercalcemia, fractures and nephrolithiasis. PC is frequently sporadic, but may occur as part of familial syndromes such as hyperparathyroidism-jaw tumor syndrome. Presurgical diagnosis is troublesome due to lack of specific biochemical and clinical features, and failure to suspect PC may compromise the ideal surgical treatment. We report in detail 9 cases of PC diagnosed and submitted to surgery at the Endocrinology Department of Irmandade da Santa Casa de Sao Paulo, a University Hospital in Sao Paulo, Brazil, between 1991 and 2016. Data was collected retrospectively from chart reviews and complemented with patient interviews. Diagnoses were established by anatomopathological findings. Seven patients were female (77.7%), three of which were sisters. Median age at diagnosis was 45 years old (range 20-55 y). Most common symptoms at diagnosis were: weight loss (66.6%), bone pain (66.6%) and fatigue (33.3%). 83.3% of patients had a palpable neck mass. Brown tumor occurred in 66.6%. All patients had nephrolithiasis and osteoporosis; 55% with pathological fracture. At diagnosis, median serum levels of PTH were 1,411 pg/ml (range 245-2,452; ref values: 12-65 pg/ml), total calcium 14.2 mg/dl (range 11.2-15.7; ref 8.3-10.6 mg/dl), phosphate 2.4 mg/dl (range 1.7-2.7; ref 2,7-4,5 mg/dl), alkaline phosphatase 2,386 U/L (range 426-4,492; ref 90-360 U/L). Median tumor size was 3.0 cm (1.2 in; range 2.0-8.0 cm, 0.8-3.2 in). Frozen section biopsy classified 50% of tumors as benign and 50% as inconclusive. Median time of follow-up after first surgery was 62 months (22-301 months). Recurrence of disease occurred in 2 subjects (22.2%), at 16 and 38 months after 1st surgery. The former was submitted to a total of 4 surgeries and radiotherapy due to recurrence at mediastinum, manubrium and clavicle, and has now no evidence of recurrence for 6months. The latter was submitted to a second surgery due to neck recurrence and in 8 months of follow-up has no sign of a new relapse. In recurrence-free subjects, mean time of follow-up with no evidence of disease is 42 months (22-301 months). The three sisters were 34, 44 and 46 years old at diagnosis. All presented weight loss and severe osteoporosis. One had brown tumor. Recurrence was seen in the one diagnosed at 46y, at 16 months after 1st surgery. The sister diagnosed at 44y had been free of disease for 22 months when she presented a fatal stroke. The third sister has no evidence of disease 158 months after 1st surgery. In conclusion, we report nine cases of PC with a long follow-up after surgery and a low recurrence rate as compared to other cohorts. Better knowledge of this rare disorder will lead to improved clinical management and patient counseling.

 

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