Prolactinoma gigante: relato de caso

Abstract

Objective: To report the clinical case of an adolescent with a giant prolactinoma, diagnosed at the pediatric endocrinology service of a public university hospital in Salvador, Bahia. Case report: A 14-year-old male adolescent presented with progressively worsening headaches and blurred vision for 2 years, culminating in sudden amaurosis in the right eye, associated with the interruption of pubertal progression. Physical examination revealed right strabismus and left eyelid ptosis, Tanner stage G2P2, and micropenis. Magnetic resonance imaging (MRI) of the pituitary-hypothalamus showed a solid-cystic expansive lesion in the sellar and suprasellar region, compressing the optic chiasm, measuring 4.0 x 4.2 x 3.0 cm. Laboratory evaluation showed hyperprolactinemia [>470 ng/dL (4.04-15.2)] and central hypothyroidism [Free T4: 0.811 ng/dL (0.93-1.71); TSH: 2.08 µUI/mL (0.27-4.2)]. Due to a suspected diagnosis of craniopharyngioma, he underwent neurosurgery and partial resection of the tumor, which had a macroscopic appearance of a pituitary adenoma. Post-operative examinations revealed hypopituitarism (deficiency of LH, FSH, ACTH, and TSH) with markedly elevated hyperprolactinemia [diluted prolactin: 3,598 ng/mL (4.04-15.2)]. Anatomopathological and immunohistochemical studies confirmed the prolactinoma, and treatment with cabergoline was initiated. After 1 year and 3 months of treatment, prolactin levels decreased to 18.11 ng/mL (1.6-16.6) and the prolactinoma reduced to 0.8 x 0.6 cm. Discussion: Prolactinomas have low prevalence in pediatrics but are more invasive and typically arise during puberty. Common clinical manifestations include headaches, visual disturbances, galactorrhea, and pubertal delay, related to the mass effect of the lesion or secondary to hyperprolactinemia. MRI of the pituitary-hypothalamus is the gold standard imaging study for diagnosis and monitoring, associated with prolactin level measurement. This is directly proportional to tumor size, being >200 ng/dL in macroprolactinomas. Dopaminergic agonists are the first-line treatment, with surgical intervention necessary in neurological emergencies or in the absence of response to medical treatment. Conclusion: Prolactinomas are tumors that present signs and symptoms over an extended period; therefore, careful investigation of headaches in young individuals, along with appropriate testing, is essential. Treatment with a dopaminergic agonist is generally effective in reducing both the tumor and prolactin levels.