Isolated Lymphocytic Infiltration of Pituitary Stalk Preceding the Diagnosis of Germinoma in 2 Prepubertal Children Treated with Growth Hormone

Abstract

We report the clinical course of 2 patients with central diabetes insipidus and evolving to panyhypopituitarism which prompted the diagnosis of an isolated pituitary stalk thickening (PST). In both patients, all etiological investigations were normal and the first biopsy revealed an isolated lymphocytic infiltrate with no sign of malignancy. Close clinical follow-up accompanied by serial brain MRIs was proposed to determine a precise diagnosis and for early detection and treatment of neoplastic disease. In our first case, the diagnosis of germinoma was made 9 months after the PST diagnosis owing to tumor progression. In the second case, the time course was even longer with the diagnosis of germinoma 6 years following initial presentation. In these cases, it is speculated that the lymphocytic infiltrates represent the first sign of a host reaction to an occult germinoma. To our knowledge, this is the third case reported of lymphocytic infiltrates preceding a germinoma in a prepubertal girl, and the only case reported in a prepubertal boy. These cases underline the difficulties in establishing the diagnosis of germinoma in a patient with isolated PST.

Suprasellar Germinoma with Chronic Hypernatremia, Adipsic Diabetes Insipidus and Hypopityuitarism. Case Report

“…Lymphocytic hypophysitis might present as a pituitary stalk thickening and this often causes difficulties in the differential diagnosis. Sometimes, the first sign in pubertal children of a host reaction to an occult germinoma may appear as a true lymphocytic infiltrate (6). A similar case to ours was described by Edouard T. who reported two prepubertal children with pituitary stalk thickening preceding the diagnosis of germinoma (6).…”

Predictors of neoplastic disease in children with isolated pituitary stalk thickening

“…Pituitary stalk biopsy entails a risk of injury to the pituitary stalk, with resultant anterior and/or posterior pituitary hormone dysfunction. Further, the predictive value of a negative biopsy may be limited: as our series suggests, it is not unusual for germinoma to histologically masquerade as hypophysitis [24,25]. Sampling error may similarly obscure the diagnosis of LCH [5].…”

Antibodies Against Hypothalamus and Pituitary Gland in Childhood-Onset Brain Tumors and Pituitary Dysfunction

“…Hypothalamic-pituitary (HP) dysfunction in subjects with intracranial mass involving the sellar and parasellar region may be due to several causes including the local compressive effect, inflammation, and or infiltration by the primary lesion, neurosurgery, and or radiotherapy (1). The differential diagnosis of HP tumors may be challenging despite a prompt biopsy because of lymphocyte infiltration of the central nervous system (CNS) tissues as a host reaction (2)(3)(4).…”

“…Hence, inflammatory lesions of the pituitary/pituitary stalk/hypothalamus including the chronic lymphoplasmacytic process known as lymphocytic infundibulo-hypophysitis, autoimmune hypophysitis, granulomatous inflammation, and xanthomatous hypophysitis (1,11,12) may raise diagnostic difficulties with tumors like germinomas. Both lymphocytic hypophysitis with central diabetes insipidus (CDI) and subsequent hypopituitarism masking a suprasellar germinoma, and isolated lymphocyte infiltration of pituitary stalk preceding the diagnosis of germinoma were reported (2)(3)(4). In addition, antipituitary antibodies (APA) and antihypothalamus (AHA) are often seen in patients with different pituitary pathologies including hypopituitarism, central hypothyroidism, acromegaly, adenomas, CDI, and in patients with Prader-Willi syndrome associated with hypothalamic dysfunction (13)(14)(15)(16)(17)(18)(19)(20)(21).…”