abnormal neuroendocrine gland morphology abnormal pineal gland morphology MP:0000632 MPheno.ontology abnormal conarium morphology abnormal corpus pineale morphology abnormal epiphysis cerebri morphology abnormal glandula pinealis morphology abnormal pineal body morphology abnormal pineal glands any structural anomaly of the unpaired epithalamic structure that is shaped like a tiny pine cone and located above the posterior commissure near the level of the habenular complex and the sylvian aqueduct; it is both a circumventricular organ and an endocrine organ that secretes melatonin, a serotonin-derived hormone involved in the regulation of circadian rhythms; the pineal parenchyma, consisting of pinealocytes, interstitial (glial-like) cells, phagocytes and capillaries, is arranged into large folliculi separated by septae of connective tissue and blood vessels pineal gland dysplasia abnormal epithalamus morphology