Multiple miliary osteoma cutis is a distinct disease entity: Four case reports and review of the literature

R. M. Myllylä, K. M. Haapasaari, R. Palatsi, E. L. Germain-Lee, P. M. Hägg, J. Ignatius, J. Tuukkanen

Research output: Contribution to journalArticle

Abstract

Background: Multiple miliary osteoma cutis (MMOC) is a rare nodular skin disease characterized by tiny bone nodules which usually form on the facial skin, typically in middle age. The aetiology of this phenomenon is poorly understood. Objectives: To search for possible bone formation progenitors and to look for a possible association with mutations in the GNAS gene (encoding the G-protein α-stimulatory subunit) and related hormonal parameters in patients with MMOC. We also reviewed the literature and discuss the aetiology and pathogenesis of adult-onset primary osteomas. Methods: We report four cases of MMOC. Histological samples were analysed for bone morphogenetic protein (BMP)-2, BMP-4 and oestrogen receptor-α known to be involved in bone formation. Endocrinological laboratory investigations and hand X-rays were performed to exclude a systemic disease. The GNAS gene was sequenced from DNA extracted from peripheral blood in all four patients and from a skin sample in one patient to exclude somatic mutations. Results: Histological analyses revealed intramembranous cutaneous bone formation resembling the findings seen in GNAS gene-based osteoma cutis disorders. However, we did not find any germline or somatic GNAS gene mutations in our patients and all laboratory investigations gave normal results. BMP-2 and -4 were expressed normally in MMOC samples, but oestrogen receptor-α was not expressed. Altogether 47 MMOC cases, 41 female and six male, have been published between 1928 and 2009. Of these cases, 55% had a history of pre-existing acne and only 15% had extrafacial osteomas. Conclusions: MMOC is a rare but distinct disease entity of unknown aetiology. Histologically, the tiny nodular osteomas show intramembranous superficial ossification but the aetiology appears to be different from GNAS-related disorders. The osteomas seem to increase slowly in number after appearing in middle age.

Original languageEnglish (US)
Pages (from-to)544-552
Number of pages9
JournalBritish Journal of Dermatology
Volume164
Issue number3
DOIs
StatePublished - Mar 1 2011

ASJC Scopus subject areas

  • Dermatology

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    Myllylä, R. M., Haapasaari, K. M., Palatsi, R., Germain-Lee, E. L., Hägg, P. M., Ignatius, J., & Tuukkanen, J. (2011). Multiple miliary osteoma cutis is a distinct disease entity: Four case reports and review of the literature. British Journal of Dermatology, 164(3), 544-552. https://doi.org/10.1111/j.1365-2133.2010.10121.x