Early morphea simulating patch-stage mycosis fungoides in two cases

Area of Science:

• Dermatology
• Pathology

Background:

• Morphea is a fibrosing skin disorder affecting dermis and subcutaneous tissues.
• Early morphea lacks definitive histological markers, potentially causing diagnostic confusion with other inflammatory dermatoses.
• Mycosis fungoides (MF) is a type of cutaneous T-cell lymphoma that can present in early patch stages.

Purpose of the Study:

• To report two cases of early-stage morphea that mimicked patch-stage mycosis fungoides.
• To highlight the diagnostic challenges in differentiating early morphea from MF based on initial histopathology.

Main Methods:

• Histopathologic examination of skin biopsies from two patients with early morphea.
• Analysis of initial biopsies showing lymphocytic epidermotropism and dermal-epidermal junction changes.
• Review of subsequent biopsies revealing characteristic fibrotic changes in subcutaneous tissue.

Main Results:

• Initial biopsies in both cases displayed features resembling early mycosis fungoides, including lymphocytic epidermotropism and Pautrier-like microabscesses.
• Later biopsies demonstrated replacement of subcutaneous fat with dense collagen bundles, a hallmark of morphea.
• These findings underscore the potential for histological overlap between early morphea and MF.

Conclusions:

• Early-stage morphea can present with histopathological findings that simulate patch-stage mycosis fungoides.
• Definitive diagnosis of morphea may necessitate repeat biopsies to identify characteristic fibrotic changes.
• Awareness of this diagnostic mimicry is crucial for appropriate patient management and avoiding misdiagnosis.