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Pigmented purpuric dermatosis or mycosis fungoides: A diagnostic dilemma
Najeeba Riyaz1, Sarita Sasidharanpillai1, Ettappurath N Abdul Latheef1
1Department of Dermatology and Venereology, Government Medical College, Kozhikode, Kerala, India.
Abstract:
Pigmented purpuric dermatoses (PPD), a group of vascular disorders with variable clinical picture is reported in all races and age groups with a male predilection. There are reports of mycosis fungoides manifesting as pigmented purpura as well as progression of PPD to cutaneous T-cell lymphoma. The diagnostic dilemma is compounded by PPD manifesting histological similarity to mycosis fungoides. Currently, it is believed that PPD with monoclonal T-cell population is more likely to progress to malignancy. We report a 31-year-old male patient who presented with the lichenoid clinical variant of PPD lesions that mimicked mycosis fungoides on histopathology. Gene rearrangement studies identified a polyclonal T-cell population. The patient responded to photochemotherapy, which is beneficial in both PPD and mycosis fungoides. Our case signifies the limitations of current diagnostic modalities in accurately distinguishing PPD from cutaneous lymphoma. Data on disease progression in similar cases may enable us to formulate better diagnostic definitions.
Insights
Pigmented purpuric dermatoses (PPD) can mimic mycosis fungoides, posing diagnostic challenges. This case highlights the need for better methods to distinguish PPD from cutaneous lymphoma, especially when T-cell populations are polyclonal.
Area of Science:
- Dermatology
- Oncology
- Pathology
Background:
- Pigmented purpuric dermatoses (PPD) are vascular disorders with diverse presentations.
- PPD can resemble mycosis fungoides (MF), a type of cutaneous T-cell lymphoma (CTCL).
- Histological similarities and potential progression of PPD to CTCL create diagnostic dilemmas.
Observation:
- A 31-year-old male presented with lichenoid PPD lesions clinically mimicking MF.
- Histopathology showed features suggestive of MF.
- Gene rearrangement studies revealed a polyclonal T-cell population.
Findings:
- The patient's PPD lesions responded well to photochemotherapy.
- Photochemotherapy is a treatment option for both PPD and MF.
- A polyclonal T-cell population in PPD may indicate a lower risk of malignant progression compared to monoclonal populations.
Implications:
- This case underscores the limitations of current diagnostic tools in differentiating PPD from CTCL.
- Further research on disease progression in PPD with varying T-cell clonality is needed.
- Improved diagnostic criteria are essential for accurate patient management and prognosis.
