Human eccrine hamartoma of the forearm-antebrachial organ of the ringtailed lemur (Lemur catta). A possible phylogenetic relationship?

A 31-year-old woman presented with a clinically otherwise unsuspicious area of profuse sweating on her right forearm. Without triggering agents, sweating attacks producing a clear, serous fluid were observed daily. Histopathologic examination of a biopsy specimen showed hyperplastic eccrine glands with pale, stippled cytoplasm characteristic of eccrine hamartoma. No explanation, however, has been given for the fact that several authors observed eccrine hamartomas in the same anatomical location. Adolescent lemurs of the species catta (ringtailed lemur) are equipped with a pair of antebrachial cutaneous glands located on the volar surface of the wrist. They exude a clear secretion enabling them to "brachial branch mark" their territories. Histopathologic findings in the ringtailed lemur's antebrachial organ show characteristics of both apocrine and eccrine glands. In contrast to normal apocrine glands, however, the antebrachial organs of ringtailed lemurs reach the epidermis directly and are not connected to hair follicles. According to the "biogenetic law" of Ernst Haeckel, stating that ontogeny has to be seen as a short and incomplete repetition of phylogeny, a human fetus passes all evolutional stages from a single cell via amphibians and mammals to a human being. Thus, the antebrachial organ of the ringtailed lemur may be the "phylogenetic explanation" for eccrine hamartomas of the forearm in humans. The histopathologic findings of the antebrachial organ and of eccrine hamartomas are in accordance with this hypothesis.