Parathyroid Carcinoma: A Single-Institution Experience with an Emphasis on Histopathological Features.

Parathyroid carcinoma (PC) is a rare malignancy that poses a diagnostic challenge on histologic examination. We analyzed various clinicopathologic features of PC. Pathology reports and slides were reviewed to evaluate the diagnostic histopathologic features of archived cases of PC from the years of 2004-2018. The study cohort comprised twenty cases of PC. The median age was 49 years (range 21-73 years) with equal gender distribution (M:F = 1:1). Most patients presented with symptoms of hypercalcemia (n = 7, 54%). Serum calcium and serum parathyroid hormone were elevated in all but one patient. The right inferior parathyroid was commonly involved (n = 8/14, 57%). The mean tumor size was 2.4 cm (range 0.8-3.5 cm). On frozen section examination, PC was diagnosed in 8 out of 9 cases. Vascular (n = 19/20, 95%) and soft tissue invasion (n = 10/20, 50%) were the most common characteristic histologic findings. Capsular invasion was identified in all cases. Perineural invasion or metastasis at presentation was absent in all cases. Other histological features noted were intratumoral fibrous bands (70%), nodular growth pattern (70%), moderate nuclear atypia (30%), prominent nucleoli (20%), and necrosis (20%). Regional lymph nodes were negative for metastatic disease in all cases (n = 10). Eight out of 16 patients received adjuvant radiotherapy. Follow-up was available in 16 cases (median 21.5 months). Two patients died of disease. Vascular and soft tissue invasion are the most common diagnostic histologic features of PC. Capsular invasion is important to distinguish PC from its benign counterparts. Intraoperative frozen section examination can be used for accurate diagnosis and surgical management.

Tumor-induced rickets-osteomalacia: an enigma.

Objective We report a case of pediatric thoracic tumor-induced osteomalacia (TIO) causing severe hypophosphatemic rickets with delayed diagnosis and emphasize on timely management of this rare entity. Case presentation A young boy presented with rickets since five years of age. Biochemical evaluation revealed hypophosphatemia, hyperphosphaturia, elevated alkaline phosphatase and normal calcium levels. Initially managed as hereditary hypophosphatemic rickets, he was given phosphorus supplements and calcitriol. Despite the therapy, skeletal deformities worsened requiring surgical corrections. Subsequently, he developed iatrogenic tertiary hyperparathyroidism for which he underwent total parathyroidectomy. Later on, he was found to have fibroblast growth factor-23 secreting thoracic mass (10.5 cm in largest dimension) which was excised with significant post operative improvement. Histopathology showed phosphaturic mesenchymal tumor-mixed connective tissue variant, confirming the diagnosis of TIO. Conclusion TIO, a correctable cause of hypophosphatemic rickets, should be considered in children presenting with hypophosphatemic rickets with evident mass on examination/imaging and in refractory cases.