Hereditary Progressive Mucinous Histiocytosis: New Insights Into a Rare Disease

Abstract

Hereditary progressive mucinous histiocytosis is a rare, benign, skin-limited form of non-Langerhans cell histiocytosis. We report on a 5-year-old boy who presented in infancy with self-resolving dermal nodules but later developed persistent and progressive erythematous papules on the face and scalp. Histologic evaluation revealed dermal aggregates of S-100/CD1a-negative histiocytes with abundant mucin. We present this case to highlight the evolution of the lesional morphology in infancy and early childhood and to stress the importance of histology in confirming this rare disorder.

Hereditary progressive mucinous histiocytosis: 3 different phenotypes in 3 family members

“…HPMH was thought to be a strictly female disease until the publication of 3 cases in men . Case 2 in our series corroborates that HPMH can affect men.…”

“…Furthermore, no mucin is observed in the histopathologic study and a hereditary profile has not been observed. Six other families have since been described, all under the designation of HPMH . The clinical, histopathological, and immunohistochemical features of the 15 cases published to date are summarized in Table .…”

Facial Erythematous Papules in a Young Woman

“…These lesions regress spontaneously. 2,3 It is unclear whether the infantile stage is present in all patients. The second phase starts at a later stage, in childhood and up to early adulthood.…”

“…Papules appear and keep progressing throughout life with no spontaneous resolution. 2 They are smooth, skin-colored or erythematous to red brown, ranging from 1 to 10 mm in size. The lesions are generally asymptomatic, although mild pruritus has been occasionally described.…”

“…Findings under electronmicroscopyarepathognomonicandrevealabundantvacuoles,myelin bodies, and zebra bodies in the cytoplasm of lesional histiocytes. 2,8 The progressive nature of HPMH differentiates it from nonlangerhans cell histiocytoses that present with lesions that regress spontaneously after a few years, such as multicentric reticulohistiocytosis or generalized eruptive histiocytoma. On the other hand, although nodular histiocytosis also follows a nonremitting course, it tends to have a more generalized distribution, bigger lesions with a central depression reaching up to 5 cm and associated systemic findings.…”