Acquired reactive perforating collagenosis with the histological features of IgG4-related sclerosing disease in a patient with Mikulicz's disease.

Acquired reactive perforating collagenosis has been reported in association with various conditions. To the authors' knowledge there has been no report of a patient with Mikulicz's disease showing acquired reactive perforating collagenosis. A 61-year-old Japanese man presented with non-pruritic multiple umbilicated papules with central keratotic and crusted plagues on the trunk, neck, and scalp. He had been diagnosed with Mikulicz's disease. Histologically, cutaneous biopsy showed a shallow cup-shaped lesion with a central crusted ulceration containing degenerated collagen in vertical strands, parakeratotic horny material, neutrophils, basophilic granular debris and elimination of collagen bundles from the dermis through to the epidermis. These clinical and histological findings suggested reactive perforating collagenosis. In addition, lymphocytes and plasma cells had infiltrated the dermis, with a tendency to be distributed around the sweat glands, accompanied by sclerotic fibrosis. On immunohistochemistry most plasma cells were positive for IgG and IgG4 (IgG4+/IgG+ plasma cells >50%). These histological findings of the skin were similar to findings previously reported for IgG4-related sclerosing diseases in other organs. Herein is described the first case of a patient with Mikulicz's disease showing acquired reactive perforating collagenosis accompanied by the histological features of IgG4-related sclerosing disease.