Adult cervical thymus revealed by thyroid medullary carcinoma

Area of Science:

• Endocrinology
• Surgical Pathology
• Developmental Biology

Background:

• Thyroid medullary carcinoma requires thorough surgical resection.
• Congenital anomalies of the branchial arches can manifest in the neck.
• Incidental findings during surgery can reveal rare anatomical variations.

Observation:

• A 64-year-old male with a history of resected thyroid medullary carcinoma presented with elevated thyrocalcitonin.
• Cervical thymus with a thymic microcyst and coexisting parathyroid tissue was incidentally discovered in the neck dissection specimen.
• The patient experienced persistent hypocalcemia post-resection, necessitating calcium supplementation.

Findings:

• The incidental finding of a cervical thymus containing a microcyst and parathyroid tissue is a rare developmental anomaly.
• The coexistence of thymic and parathyroid tissue in the cervical thymus highlights complex embryological development.
• Persistent hypocalcemia post-thyroid cancer resection can be linked to the disruption or removal of parathyroid tissue, even when incidentally located.

Implications:

• Recognition of rare branchial arch abnormalities, such as cervical thymus with parathyroid inclusions, is crucial for surgical planning and management of extensive thyroid malignancies.
• Understanding these anatomical variations can help predict and manage potential postoperative complications like hypocalcemia.
• This case underscores the importance of detailed histopathological examination of surgical specimens to identify all anatomical structures and potential anomalies.