Familial secreting-pinealomas : biological and preliminary genetic studies

Introduction: Sporadic pinealomas are intracranial tumors which incidence account for less than 1/107. This is the second report of secretory familial pinealoma in a mother and sister. We report for the first time neuroendocrine and preliminary genetic studies in these benign tumors.
Methods and patients: Radioimmunoassay of urinary 6-sulphatoxymelatonin (a-MT6s) was performed in patients and in 90 control subjects aged 19-67 years. Samples were collected at 19-23 , 23-07 and 07-11 h. Endocrine studies including PRL, TSH, LH, FSH, ACTH, IGF1 and tumoral markers (bHCG, NSE, CEA) levels were measured. Lymphocytes caryotype was determined by CGH. Pituitary and pineal MRI were done in both patients.
Results:
The daughter was the index case. Diagnosis was done because of headaches. Pineal MRI showed a 17 x 14x 25 mm cystic lesion with gadolinium enhancement and no ventricular dilatation. Circadian rhythm of urinary a-MT6s was present but a-MT6s levels were clearly elevated compared to age-matched controls: 1455 ng/h at 19-23hs (308  261), 6012 ng/h at 23-07hs (1423753) and 3280 ng/h at 07-11hs (579340).
The 55 years-old mother reported similar complaints during the daughter's follow-up. A pineal MRI identified a 18 x 20 x 14 mm cystic lesion. There were no signs of intracranial hypertension. None of the women reported sleep disturbances. Circadian rhythm of urinary a-MT6s was lost but a-MT6S levels were clearly elevated : 2380 ng/h at 19-23hs (173  153), 2812 ng/h at 23-07hs (768486) and 1897 ng/h at 07-11hs (480383).
Endocrine studies and tumoral markers were in the normal range. No chromosomal abnormalities were found in both women (46,XX).
Discussion: Due to the rare occurrence of sporadic pinealomas it is unlikely that such a tumor afflict two members in the same family. Although no histological proof was obtained in our patients, radiological findings and tumoral hypersecretion of melatonin derivated a-MT6s clearly suggest the pineal origin of these tumors. We suggest an autosomal dominant form of transmission with incomplete dominance as the most probable model of inheritance of familial pinealoma.