Derm Match Game: Two Leg Lesions

Case 1

DISCUSSION

Both of the photographs are from the same patient; the images depict the presenting pathology on each leg. In fact, the patient shown as Case 1 and Case 2 has cutaneous T-cell lymphoma (CTCL) of the classic mycosis fungoides variety.¹

CTCL comprises a heterogeneous group of lymphoproliferative disorders characterized by clonal replication of T-lymphocyte subsets and by disease-defining and differentiating clinical and molecular features.^2,3 Mycosis fungoides is the most common form of CTCL, accounting for 44% to 50% of all cutaneous lymphomas.³ At least 1000 new cases are diagnosed in the United States each year; the mean age at onset is in the mid–sixth decade of life.⁴

Case 1/2 is a previously healthy 60-year-old man whose skin lesions first developed about 5 to 6 months before presentation and have been increasing in size and thickness since that time. A biopsy from each morphology revealed features consistent with CTCL: a dermal band-like infiltrate of atypical lymphocytes with permeation into the epidermis (clinical photo 1) and a solid collection of similar neoplastic cells with cerebriform nuclei effacing the dermis (clinical photo 2). The atypical cells had a prototypical immunohistochemical staining pattern that identified them as associated with the CTCL/mycosis fungoides subtype.

This case beautifully illustrates the frequently sequential clinical nature of mycosis fungoides. The disorder often begins as flat, scaly patches; evolves into elevated, thick plaques; and ultimately may develop into exophytic tumor masses. This case also demonstrates why correct diagnosis may be delayed, especially early in the disease. Patch- and plaque-stage mycosis fungoides may clinically mimic tinea corporis, eczema, psoriasis, subacute lupus erythematosus, and other nonmalignant entities. Similarly, initial histological examination results may be nonspecific, and serial biopsies may be required to firmly establish a diagnosis.⁵

Both prognosis and therapy depend heavily on clinical staging. In turn, staging relies on both the morphological features and extent of cutaneous disease; the presence or absence of disease within lymph nodes; the presence or absence of visceral involvement; and the presence or absence of circulating atypical lymphocytes within the bloodstream. A detailed explanation of staging is available elsewhere.⁶

Case 2

Early-stage disease (eg, as shown in clinical photo 1) can be managed with skin-directed therapy. Options include ultrapotent topical corticosteroids, application of aqueous or ointment-based nitrogen mustard or carmustine, topical retinoids, or phototherapy (psoralen and UVA [PUVA], broad- or narrow-band UVB). Biologic therapy, such as interferon alfa or systemic administration of a retinoid such as bexarotene, may be added for more extensive disease. Various immunotherapies and single- or multi-agent cytotoxic and chemotherapeutic regimens are available for more advanced mycosis fungoides; extracorporeal photophoresis is another option.

Mycosis fungoides is typically radiosensitive; therefore, very thick or ulcerated plaques and tumor masses (such as that depicted in clinical photo 2) may be managed with lesion-directed, relatively low-dose orthovoltage radiotherapy.⁷ Total skin electron beam therapy is also used, primarily for widespread, refractory disease. An excellent review of all treatment options is available elsewhere.⁸

Many cases of mycosis fungoides run an indolent course, including a good response to almost any intervention. In contrast, other cases run a course characterized by rapid clinical deterioration and early development of cutaneous tumors and lymphatic and visceral involvement. A multidisciplinary approach, involving practitioners from dermatology, hematology, oncology, and radiation therapy, is ideal for all cases of mycosis fungoides.⁵ Patients who have complex cases might also be considered for referral to a regional interdisciplinary cancer center.