Papillary adenocarcinoma of thyroid in a patient with right submandibular mass--a rare case of 'lateral aberrant thyroid'.

BACKGROUND

Ectopic thyroid is a rare entity in the study of thyroid disease. The occurrence of ectopic thyroid tissue as a mass in the submandibular region is even rarer.

AIM: To report a case of papillary adenocarcinoma of thyroid within a right submandibular mass in a 67-year-old man. Additionally this is to alert doctors on the possibility of the condition and re-emphasize the need for proper and thorough histologic investigation.

METHOD: The case notes of the patient, who had presented a year earlier with right submandibular mass, were retrieved and studied. At the initial presentation chest radiograph and assessment of the oropharynx by an otorhinolaryngologist were carried out. Full blood count, erythrocyte sedimentation rate (ESR) and fine needle aspiration biopsy (FNAB) were done at the second presentation. An ultrasound scan of the neck and repeat chest radiograph were also performed.

RESULTS

The right submandibular mass had increased in size about 10-fold by the time the patient was seen 13 months later. The chest radiograph and oropharyngeal examination were normal. The neck ultrasound scan demonstrated the presence of a solid right submandibular mass. The FNAB showed papillary adenocarcinoma of the thyroid. He declined a near-total thyroidectomy and demanded nonsurgical treatment. Low dose L-thyroxine (0.1 mg) daily was started and referred to another centre for possible radioactive iodine treatment. This latter treatment could not be given because of lack of facilities. Follow-up review in 3 months showed that the patient was only on L-thyroxine therapy and his clinical condition had deteriorated. He was subsequently lost to follow-up.

CONCLUSION

This patient illustrates the even rarer case of a 'lateral aberrant thyroid' presenting as a malignant submandibular mass. It is probably the latest addition to the rather rare number of such cases in the literature. Doctors should be aware of the possibility of the condition and the need for proper an d thorough histologic investigation is re-emphasized.