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Primary cavernous haemangioma of the thyroid: a rare pathology

A 77-year-old female was referred with a 1-year history of an acquired, enlarging neck mass. Her past medical history included hypertension, hypercholesterolaemia, type II diabetes, atrial fibrillation (on aspirin), chronic kidney disease and ulcerative colitis. She had no relevant thyroid history, family history of thyroid cancer, ionizing radiation exposure or neck trauma. She was a lifelong nonsmoker. An obvious goitre was present on inspection (Fig. 1a). Palpation revealed a soft, large, non-tethered mass in the right anterior triangle with retrosternal extension and left tracheal deviation. There was no cervical lymphadenopathy. Normal bilateral vocal cord function was visualized on nasendoscopy despite mild dysphonia. Thyroid function tests confirmed euthyroidism (thyroid stimulating hormone (TSH): 2.88 mIU/L). Thyroid ultrasound showed that the right lobe was completely replaced by a heterogeneous, lobulated mass (9.0 × 8.0 × 5.0 cm) of low vascularity containing microcalcifications. The left lobe measured 5.0 × 1.3 × 1.0 cm with a 1.2-cm hypoechoic lower pole nodule. Computed tomography of the neck demonstrated a large, heterogeneous mass (8.0 × 8.0 cm) extending to the sternal notch causing laryngotracheal deviation to the left with minimal compression (Fig. 2). Initial fine needle aspiration biopsy (FNAB) of the right mass was non-diagnostic, and the left nodule was benign. Repeat right FNAB showed multiple fragments of non-epithelial stromal tissue without follicular cells or colloid. The specialist pathology service performed a core biopsy to assist diagnosis. This showed a meshwork of vascular spaces lined by endothelial cells, confirmed by positive CD31 and negative thyroglobulin immunoperoxidase. There was no pleomorphism or mitotic activity. Appearances were consistent with a vascular neoplasm, most likely a cavernous haemangioma. The patient was discussed at a multidisciplinary team meeting, and the consensus was to proceed with a right hemi-thyroidectomy. Percutaneous angioembolization was considered as non-operative management as the patient’s age and comorbidities placed her in a moderateto high-risk surgical category. However, following computed tomography angiography and consultation with interventional radiology, this was considered high risk due to a short superior thyroid artery stump and moderate carotid artery stenosis. The patient underwent a right hemi-thyroidectomy without complication (Fig. 1b,c). The mass was mildly vascular in nature, non-tethered and dissected free with minimal haemorrhage. Macroscopic histopathological assessment found a 10.0 × 7.0 × 7.0 cm, 170 g right thyroid with a smooth intact capsule containing a 6.0 × 5.5 × 5.0 cm circumscribed haemorrhagic lesion with central fibrosis (Fig. 3a). Microscopically, a circumscribed benign vascular lesion was seen with areas surrounded by a partial fibrotic capsule with surrounding haemorrhage, chronic inflammation, calcifications and a compressive effect on normal thyroid parenchyma (Fig. 3b). The lesion was further characterized by positive endothelial markers (CD31, CD34 and factor 8) and negative epithelial markers (cytokeratin MNF-116, thyroglobulin and thyroid transcription factor-1) (Fig. 3c). Histopathology confirmed a primary cavernous haemangioma of the thyroid. The patient’s post-operative course was unremarkable.