A 75-year-old Japanese man was referred to us and complained of multiple ulcers on his left forearm and right lower leg. He underwent amputation of the right second toe with unknown cause at the age of 18. Since then, he had suffered from recurring skin ulcers on the left forearm and right lower leg for nearly 60 years. At the initial visit, irregular well-circumscribed brown atrophic aspects were seen on the left arm and from the dorsum of the right foot to the anterior surface of the right lower leg. The center of the atrophic region contained many ulcers with dilated capillaries and crust. On laboratory examination, the results of a chest roentgenogram and angioechogram were normal, and the only abnormal finding was a slightly elevated level of CRP in plasma. Fungus and acid-fast bacillus cultures were negative. A histopathological examination revealed a palisading granuloma surrounding degenerated collagen fibers, which extended through the deep dermis into subcutaneous tissue. The ulcerative lesions were refractory to various conventional treatments.

A 44-year-old male who had no medical history was admitted to our hospital complaining of a four-month history of sudden-onset multiple ulcers on the left thigh. Physical examination revealed ulcerative lesions with multiple small pustules on the left thigh. Laboratory examination showed an increased number of leukocytes (13,610/mm³) with 93.2％ neutrophils and elevated CRP (4.35 mg/dL). Histological examination showed neutrophilic infiltration into the mid- to lower dermis, especially around the hair follicles. The diagnosis of unilateral pustular pyoderma gangrenosum was made. Systemic prednisolone, cyclosporine A, and sulfasalazine were initiated after treatment with mini pulse steroid therapy (methylprednisolone at 500 mg/day for five days). Despite the decreased inflammatory response, the patient suffered from multiple painful ulcers, which were successfully treated with negative-pressure wound therapy (NPWT) starting 66 days after admission. Rapid re-epithelization and pain reduction could be achieved with NPWT in this case.

A 65-year-old Japanese woman with an eight-month history of reticular macular erythema on the midlines of her back and chest was referred to our hospital. She had a history of MALT lymphoma and Takayasu arteritis, and had been treated with oral prednisolone (5 mg/day) for Takayasu arteritis. Histopathological examination of a biopsy from the erythema revealed perivascular lymphocytic infiltrates and mucin deposition in the superficial dermis. Based on the clinical and histopathological findings, a diagnosis of reticular erythematous mucinosis (REM) was made. Antimalarial agents are known to be effective in the treatment of REM, but antimalarial agents were not approved in Japan at the time. Thus, although topical and oral steroids are generally not effective against REM, we administered topical betamethasone butyrate propionate to the lesions. Soon after the administration of the topical steroid, the lesions improved gradually. Two months after the administration, oral prednisolone was increased to 10 mg/day, and the lesions almost completely cleared.

An 83-year-old woman noticed multiple red tumors on her left ear three months before her first visit to our department. Clinically, multiple reddish tumors were present on the preauricular area of her left ear. Histologically, CD30-positive and ALK-negative large or medium-sized atypical lymphocytes proliferated in the entire dermis with massive inflammatory small lymphoid cell infiltration. The patient had no extracutaneous lesions including bone marrow ; therefore, she was diagnosed with primary cutaneous anaplastic large cell lymphoma (PCALCL). Electron beam-irradiation therapy at the total dose of 40 Gy led to complete remission of all the tumors ; however, yellowish nodules remained on the affected area. Histologically, numerous foamy cells were found in the dermis without any CD30⁺ atypical tumor cells, supporting the diagnosis of dystrophic xanthomatization caused by radiation therapy for PCALCL. We also summarize and discuss the characteristics of six other reported cases of dystrophic xanthomatization associated with PCALCL.