Monomorphous Plurihormonal Pituitary Adenoma of Pit-1 Lineage in a Giant Adolescent with Central Hyperthyroidism

Abstract

Thyrotropin (TSH)-secreting pituitary adenomas are exceedingly rare at the pediatric age and no cases of co-secretion with other pituitary hormones in these tumors have been described in this age range. We present a case of a monomorphous plurihormonal pituitary adenoma that co-secreted TSH and GH in a pediatric patient. A 13-year-old male presented with increasing height velocity (17.75 cm/year, 9.55SD), weight loss, and visual impairment. Initial biochemical evaluations revealed secondary hyperthyroidism. A giant pituitary tumor compressing the surrounding structures was detected by magnetic resonance, and a transsphenoidal surgery was initially performed. Pathological examinations revealed an atypical, monomorphous plurihormonal Pit-1 lineage tumor with mixed features of silent subtype 3 adenoma and acidophil stem cell adenoma. In the postoperative period, secondary hyperthyroidism recurred with high levels of both GH and IGF1. In addition, due to tumor re-growth, a multimodality treatment plan was undertaken including surgery, somatostatin analogs, and radiotherapy. We report the first pediatric case of a plurihormonal TSH- and GH-secreting pituitary adenoma, further expanding the clinical manifestations of pediatric pituitary tumors. Comprehensive pathological evaluation and close follow-up surveillance are crucial to the prompt delivery of the best therapeutic options in the context of this particularly aggressive pituitary tumor.

Silent subtype 3 pituitary adenomas are not always silent and represent poorly differentiated monomorphous plurihormonal Pit-1 lineage adenomas

“…Similar to a recent case that we reported but did not include in this cohort, 23 our results also highlight that silent subtype 3 adenomas should be added to the list of Pit-1 lineage adenomas that can present with scattered fibrous bodies, similar to acidophil stem cell adenomas, [3][4][5] which also express Pit-1. However, acidophil stem cell adenomas are distinguished from silent subtype 3 adenomas by their oncocytic nature and predominant diffuse cytoplasmic staining pattern for PRL with only focal GH expression to indicate plurihormonality in some cases.…”

Transcriptome and methylome analysis reveals three cellular origins of pituitary tumors

“…This clustering of CNFPA was previously reported by our group 19 and correlates with the clinical behavior of these tumors 20 . Similarly, the clustering of POU1F1-dependent tumors is congruent with the finding of plurihormonal tumors capable of synthesizing GH, PRL and TSH in different combination 21 . Thus, it appears that these three transcription factors drive not only normal gland cytodifferentiation but also pituitary tumorigenesis.…”

Plurimorphous plurihormonal Pit-1 positive macroadenoma with central hyperthyroidism: a rare case report and literature review

“…Simultaneously, some patients showed acromegaly with hyperprolactinemia (11) or hyperthyroidism (16,17). Plurihormonal TSHomas with hypersecretion of GH revealed acromegaly usually masks secondary hyperthyroidism (17,18). A unique study revealed a plurihormonal TSHoma hypersecretion of TSH, GH, and FSH (14).…”