Parathyroid Adenoma with Macrofollicular Growth Pattern: A Rare Histopathological Entity.

The majority of parathyroid adenomas can be localized preoperatively using various imaging techniques. The success rate of focused parathyroidectomy exceeds 95% when performed by an experienced surgeon. Here, we report an apparent failure of focused right inferior parathyroidectomy performed for a preoperatively detected parathyroid adenoma. This misinterpretation arose due to macrofollicular growth pattern of the resected parathyroid adenoma, which mimicked thyroid tissue. The patient subsequently underwent re-exploration, including intraoperative ultrasound, which revealed that the culprit gland had, in fact, been successfully removed during the initial surgery. This finding was also supported by a significant decrease in the intraoperative parathyroid hormone level, as compared to the pre-operative level. This case highlights the rare macrofollicular histology of parathyroid adenoma and underscores the importance of a multidisciplinary team in successfully treating the condition.