Eccrine Squamous Syringometaplasia Mimicking Acute Cutaneous GVHD in a Pediatric HSCT Recipient: Case Report and Brief Review of the Indexed Literature.

Eccrine squamous syringometaplasia (ESS) is an uncommon reactive alteration of eccrine ducts, most often reported in oncologic and transplant settings, where it may clinically mimic acute cutaneous graft-versus-host disease (GVHD). We describe a 3-year-old boy with chronic granulomatous disease who developed a diffuse erythematous eruption 6 weeks after haploidentical hematopoietic stem cell transplantation. Clinically suggestive of acute GVHD, histopathologic examination instead revealed spongiotic dermatitis with prominent squamous metaplasia of eccrine ducts, in the absence of interface dermatitis, keratinocyte apoptosis, or satellitosis, supporting a diagnosis of ESS. The eruption resolved with topical corticosteroids without modification of systemic therapy. We also provide a brief review of Scopus/PubMed-indexed literature, summarizing reported clinical settings, triggers, histopathologic features, and outcomes. Clinicopathologic correlation is essential in transplant recipients to distinguish ESS from GVHD and to avoid unnecessary escalation of immunosuppression.