Diencephalic syndromeおよび思春期早発症を呈した視床下部腫瘍の一例

HYPOTHALAMIC GLIOMA WITH DIENCEPHALIC SYNDROME AND FOLLOWING PRECOCIOUS PUBERTY: A CASE REPORT

　抄録　diencephalic syndromeを呈した視床下部神経膠腫例において，経過中に思春期早発症を併発した一例を報告し，内分泌学的検討をくわえた。症例は生後4ヵ月頃より体重の増加が障害され，1歳10ヵ月頃より歩行障害，眼振，嘔吐が出現。CTにて第3脳室を占める腫瘍と側脳室の拡大を認めた。脳室—腹腔シャント術後，症状の改善と異常高値を示した血中成長ホルモン（GH）の正常化を認めた。ついで部分摘出，放射線治療により，腫瘍の著明な縮小が認められた。組織はpilocytic astrocytomaであった。その後，MRI上腫瘍の増大は認められなかったが，3歳6ヵ月頃より乳腺の肥大をきたし内分泌検査にてLH,FSH,E1，E2の基礎値の増加，LHRH負荷にてLHの過剰反応および夜間LH,FSHの上昇を認め，思春期早発症と診断した。diencephalic syndromeおよび思春期早発症の発症機序につき考察をくわえた。

A 1-year 11-month-old girl was admitted for losing her weight and gait disturbance. At 4 months of age, she began to become emaciated inspite of normal food intake. Physical and neu-rological examinations were normal except for a marked lack of subcutaneous fat, irritability and nystagmus. CT scans demonstrated a large tumor occupied in the third ventricle and marked dila-tation of the lateral ventricles. Endocrinological studies revealed high levels of plasma growth hormone (GH) in contrast with normal levels of somatomedin-C. The basal value of GH returned to normal with a subnormal response to insulin subsequently after VP-shunt. Then, a pilocytic astrocytoma was partially resected with trans-callosal approach. Postoperative course was un-eventful and her growth rate returned to normal range. CT scans after radiation therapy of 49 Gy showed marked decrease in size of the tumor. At 3 years and 6 months of age, enlargement of her breast was pointed out although MRI indicated no enlargement of the tumor. Basal value of LH, FSH, E 1 and E 2 elevated and LHRH test showed over-response of LH and FSH. Other hypothalamic-pituitary functions were partially preserved.

Case of precocious puberty following dience-phalic syndrome associated to the hypothalamic and/or optochiasmatic glioma is quite rare in the previous literature. Mechanisms of diencephalic syndrome and following puberty are unclear. However, endocrinological and radiological find-ings observed in the present case suggest that hormonal disfunction might be due to the failure of inhibition on GH and LHRH secretion mecha-nism in the anterior hypothalamus.