Endocrine Abstracts

Introduction: Primary hyperparatyhyroidism (PHPT) is usually caused by single or multiple adenomas and cancer is rare accounting for <1% of all presentations. The presence of certain cytological and architectural features such as adherence to adjacent organs, a solid growth pattern, broad bands of fibrosis, cytological atypia, and an irregular growth contour do not indicate malignancy but are recognised as atypical features encountered more commonly in malignant than benign tumours. Tumours that demonstrate these atypical features and do not fulfill criteria for carcinoma can be classified as atypical adenomas. Herein we aimed to evaluate the clinical and biochemical features of the patients histopathologically diagnosed with an atypical parathyroid adenoma.

Method: Our endocrine database was searched retrospectively for the patients with operated PHPT and diagnosed with atypical adenoma. Demographic, clinical, and biochemical data of the patients were recorded. A control group was formed from the patients who were also operated with the diagnosis of PHPT and classical parathyroid adenoma was detected histopathologically.

Results: There were 16 patients in the atypical adenoma group and thirty patients in the control group. Age and gender distribution of the patients were similar in between groups with female predominance. Serum Ca and P levels were also similar where as preoperative serum PTH, ALP, and urinary Ca excretion were significantly higher in patients with atypical adenoma (P<0.001, P<0.001, and P=0.021 respectively). Adenoma size was significantly higher in the atypical adenoma group compared to controls (P=0.006) and cystic degeneration and isoechoic appearance on USG were more prevalent among the atypical adenomas (P=0.016).

Conclusion: Preoperatively high PTH, ALP, and urinary Ca levels may be predictive for atypical adenoma or carcinoma within a patient being evaluated for PHPT. The surgeon might prefer enbloc parathyroidectomy instead of minimal invasive surgery in such cases with more strict postoperative follow up.