Fissured Tongue associated with Hypothyroidism in a Young Patient.

Fissured tongue is a benign oral condition characterized by grooves or fissures on the dorsal surface of the tongue and is often considered idiopathic. However, it has occasionally been reported in association with systemic disorders, including endocrine abnormalities. We report the case of an 18-year-old male who presented with fatigue, cold intolerance, weight gain, and progressive fissuring of the tongue over several years. Intraoral examination revealed multiple prominent fissures on the dorsal surface of the tongue with mild macroglossia. Laboratory investigations demonstrated elevated thyroid-stimulating hormone levels with borderline low free thyroxine and mildly raised antithyroid peroxidase antibodies, findings suggestive of hypothyroidism possibly related to autoimmune thyroid disease. The patient was started on levothyroxine therapy, resulting in improvement of systemic symptoms and normalization of thyroid function tests within 6 months. However, the fissured appearance of the tongue persisted despite biochemical euthyroidism. This case is noteworthy because the patient was a young adult with progressive tongue fissuring preceding diagnosis, a positive family history of thyroid disease, and persistence of fissures despite appropriate thyroid hormone replacement therapy. The report highlights the potential association between oral findings and systemic endocrine disorders and emphasizes the importance of careful oral examination in patients presenting with suggestive systemic symptoms.