Segmentally-arranged cutaneous mucinosis ranging from papulonodules to sclerotic pigmented macules

ARTICLE

Auteur(s) : Yujiro Hayashi, Eri Araki, Yosuke Yagi, Miyachi Yoshiki, Atsushi Utani

Department of Dermatology, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan

Papular mucinosis (PM) is characterized by mucin deposition in the dermis without systemic disorders and is divided into subgroups such as discrete papular, acral persistent papular, nodular form and cutaneous mucinosis of infancy [1]. We present a case of cutaneous mucin deposition which initially developed as papules and nodules in a segmental distribution pattern and gradually changed to brownish sclerotic macules. We propose that this is a novel case of a subgroup of PM with segmental distribution.

A 24-year-old male had skin-colored nodules and papules on the right forearm at 3 years of age. Histopathological assessment of a nodule demonstrated mucin deposition and was diagnosed as a type of mucin deposition. Since then, a dozen lesions developed on the right arm and the right side of the trunk, distributed in a segmental pattern (figure 1E). He said most lesions slowly flattened and pigmented with sclerosis (figures 1A, B). Several months previously, a subcutaneous nodule developed on the right upper arm, although new lesions had not developed for the last 10 years. Physical examination revealed brown sclerotic oval pigmented macules, 1-4-cm in diameter, on the right arm and shoulder, and on the right back and abdomen with segmental distribution (figure 1). A few, small, < 1-cm diameter, white or skin-colored, firm, dome-shaped, waxy papules were also found on the abdomen and dorsa of the right hand and fingers (figures 1B, D). Biopsy specimens were taken from a recently appeared, firm, subcutaneous nodule on the medial right upper arm and from a pigmented sclerotic macule on the right forearm (figure 1C). The histopathological examinations showed that the subcutaneous nodule had abundant glycosaminoglycan (GAG) deposition in the entire dermis (figures 2A-C). The pigmented macule also had significant GAG deposition and abnormally increased and thickened collagen bundles were detected in the pigmented macule (figures 2D-F). The elastic fibers were shorter and thinner in the subcutaneous nodule (figures 2C, F). The biopsied specimens from the subcutaneous nodule and an age and sex matched control upper arm were simultaneously examined by biotin-conjugated hyaluronan binding protein (1 μg/mL Seikagaku Corporation, Tokyo, Japan), and followed by streptavidin-Cy3 (Jackson ImmunoResearch inc. PA, USA). Hyaluronan accumulated in the nodular lesion considerably more than in the control dermis (figures 2G, H). Excessive hyaluronan deposition was also detected in the sclerotic pigmented lesion (figure 2I).

Diseases that are characterized by the deposition of mucin in the dermis without other systemic diseases should be considered, including PM, self-healing cutaneous mucinosis, and mucinous nevus. None of these cases have been reported changing to sclerotic lesions. A rare case of linear nodular morphea was reported [2], which had similar features, such as localized sclerotic lesion and nodular mucin deposition. However, unlike our case, the linear sclerotic lesions preceded the development of nodular lesions by approximately 1-year in that case.

The present case has no family history, but two separate segmental distributions suggest that genetic mutation is involved as a causative factor during the embryonic stages. No skin disorders outside of the lesion suggested our case most likely belongs to type I of segmental manifestations as proposed by R. Happle [3]. A nodular form of PM was most fitted to the diagnosis of the nodular lesion on the upper arm. However, in PM, fibrosis is not marked and may even be absent [4] and sclerotic changes in PM have not been reported so far. These genetically abnormal mesenchymal cells may change their phenotype in producing matrix components from GAG to collagen. We propose that our case may be a variant of PM and may denote segmental PM.

Acknowledgements

References

2 Jain K, Dayal S, Jain VK, et al. Blaschko linear nodular morphea with dermal mucinosis. Arch Dermatol 2007; 143: 953-5.

3 Happle R. Segmental forms of autosomal dominant skin disorders: different types of severity reflect different states of zygosity. Am J Med Genet 1996; 66: 241-2.

4 Rongioletti F, Rebora A. Cutaneous mucinoses: microscopic criteria for diagnosis. Am J Dermatopathol 2001; 23: 257-67.