Ectopic lingual thyroid presenting with massive hematemesis
Ectopic thyroid tissue is a rare embryological anomaly which appears during the migration of the thyroid anlage from the primitive foregut to its final position in the pre-tracheal region of the neck. According to autopsy series the prevalence of ectopic thyroid tissue varies between 7% and 10%. It can be found in the midline, laterally in the neck, mediastinum, or even under the diaphragm and other sites such as axillary, pituitary and adrenal gland, genitourinary and gastrointestinal tract. Approximately 90% of ectopic thyroid tissue is found in the lingual thyroid area that is usually localized in the posterior third of the base of tongue. The pathogenesis of lingual thyroid caused by migration defect is not fully known but maternal immunoglobulins leading to block TSH induced thyroid growth may play a role.

A 33-year-old man was referred to emergency department with complaint of coffee ground emesis for two days. Direct physical examination of oral and nasal mucosae failed to reveal a bleeding focus. Upper gastrointestinal endoscopy examination revealed fresh blood in the stomach, without any evidence of mucosal abnormalities in the esophagus and stomach. His serum hemoglobin and hematocrit levels were 7 g/dL and 25% respectively. Two units of erythrocyte suspension were transfused. Four hours later, hematemesis stopped spontaneously. On laryngoscopic examination, a smooth mass obstructing the visualization of the larynx with reddish surface covered with vessels and bleeding focus was found at the base of the tongue that was considered as ectopic lingual thyroid.

Thyroid ultrasonography revealed no orthotropic thyroid gland in normal region. Thyroid scintigraphy with technetium-99m (Tc-99m) showed an increased focal uptake in the tongue base consistent with lingual thyroid without any Tc-99 m uptake in the normal thyroid location. Magnetic resonance imaging (MRI) exam revealed a mass, 40 x 36 x 51 mm in size with no invasive features indicated a lingual thyroid without a thyroid gland in the normal location. Thyroid hormone tests showed elevated TSH: 39 mIU/L (reference value 0.3–5.5 mIU/L), low FT3: 0.5 ng/dL (reference value 0.7–1.8 ng/dL) and normal FT4: 1.52 ng/dL (reference value 0.89-1.78 ng/dL).

Lingual thyroid is frequently benign therefore histologic confirmation is usually not necessary, but rarely can harbor malignancy. Incidence of carcinoma in lingual thyroid is estimated to be approximately 1 in 100 cases that majority of these tumors are follicular type not papillary in contrast to typical thyroid tumors.

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