Macroglossia

Macroglossia is the medical term for unusual enlargement (hypertrophy) of the tongue. Severe enlargement of the tongue can cause cosmetic and functional difficulties including in speaking, eating, swallowing and sleeping. Macroglossia is common in primary and myeloma-related amyloidosis. Amyloidosis is an accumulation of insoluble proteins in tissues that impedes normal function. (Merck Manual 17th Ed.) Macroglossia is also a clinical feature in congenital hypothyroidism, rare genetic syndromes such as Beckwith-Wiedemann syndrome and immunodeficiency, centromere instability and facial anomalies syndrome, acromegaly and Hurler syndrome.
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Mac·ro·glos·si·a n. Enlargement of the tongue. Also called megaloglossia, pachyglossia. macroglossia, n an increase in the size of the tongue due to [more]Macroglossia - Community and Resources

Noun
1. a congenital disorder characterized by an abnormally large tongue; often seen in cases of Down's syndrome
(hypernym) birth defect, congenital anomaly, congenital defect, congenital disorder, congenital abnormality

(n.)
Enlargement or hypertrophy of the tongue.
  

Enlarged tongue.