Skin lesions after hematopoietic stem cell transplantation: Graft-versus-host disease versus true dermatomyositis

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Chronic graft-versus-host disease (cGVHD) is an alloimmune and autoimmune complication of hematopoietic stem cell transplantation (HSCT). It is well documented that cGVHD may develop in some cases after allo-HSCT, representing a variety of symptoms closely similar to those in autoimmune diseases. Sometimes true autoimmune diseases can also develop. The occurrence of autoimmune diseases after allogeneic HSCT is infrequent and difficult to interpret due to the reconstitution of the immune system and the multifactorial origin of most of these diseases.^{1, 2}

We present a case of a patient who developed a cGVHD with identical cutaneous manifestations to dermatomyositis. A 45-year-old-woman with a previous history of acute myeloid leukemia was treated with an allogenic HSCT. She developed an acute graft-versus-host disease with cutaneous involvement with good response to steroids and sirolimus.

Six months later cGVHD intestinal symptoms began. In addition, scaling plaques on the scalp and adjacent to the back of metacarpophalangeal and interphalangeal joints appeared (Figure 1). She had similar scaly plaques on the eyelids and a slight Gottron sign was noticeable on the elbows. Capillaroscopy of the nail fold showed a normal pattern.

A cutaneous biopsy was performed showing epidermal hyperplasia, hypergranulosis, and parakeratosis. Superficial interface dermatitis with vacuolar changes in the basilar layer was noted with a lymphocytic infiltrate in a band pattersn distribution (Figure 2). Apoptotic keratinocytes were observed within the epidermis (Figure 3).

This supported the diagnosis of dermatomyositis-like cGVHD. Muscle symptoms were not reported by the patient. CK and aldolase levels were normal. Antinuclear antibody testing was negative with decreased levels of C3. Myositis antibody-specific blot was negative.

One year after transplantation, the patient died of respiratory sepsis with a torpid course.

Dermatomyositis-like presentations after HSCT are very rarely reported. It can appear between 4 and 52 months after HCST. Skin manifestations may be identical to dermatomyositis. Cases with muscle involvement confirmed by muscle biopsy and severe cases with progressive interstitial lung disease associated with MDA5 antibodies have also been described.³

cGVHD histological findings are not specific and diagnosis requires clinicopathological correlation. Also, common histological features can be found in skin biopsies of dermatomyositis and cGVHD. Most representative histopathological findings in cutaneous dermatomyositis include interface dermatitis, mucin deposits, and perivascular inflammation. In contrast, a lichenoid infiltration pattern and apoptotic keratinocytes are more common in cGVHD.

The distinction between dermatomyositis-like cGVHD and a true dermatomyositis is complex. The isolated finding of complete chimerism of donor lymphocytes in peripheral blood of the receptor does not allow establishing the diagnosis of GVHD due to the persistence of receptor cells with immunogenic potential.^{4, 5} It has been suggested that the determination of chimerism in the immune cells of the affected tissue could help to distinguish between GVHD and an autoimmune disease. FISH analysis on a muscle specimen can determine whether there is a predominance of CD4⁺ T lymphocytes from the recipient (in favor of an autoimmune process) or CD8⁺ lymphocytes from the donor (in favor of graft-versus-recipient disease).^{6, 7}

Our patient presented chimerism of 97% of donor lymphocytes in peripheral blood. No specific data on dermatomyositis was obtained by skin biopsy. Given the fatal clinical course, no muscle biopsy was performed. Therefore, the diagnosis of dermatomyositis-like cGVHD was performed corresponding to an alloimmune process associated with HSCT.

None.