Hyperpigmentation as a peculiar presentation of mycosis fungoides

Hyperpigmented Mycosis Fungoides Masquerading as Longstanding Lichen Planus Pigmentosus: A Diagnostic Pitfall

BACKGROUND

Mycosis fungoides (MF) is a rare primary cutaneous T-cell lymphoma, accounting for 50%-60% of all cutaneous T-cell lymphoma cases. It has a prevalence of approximately 5-6 cases per 1 million people annually and a higher incidence in dark-skinned populations.

CASE PRESENTATION

We report a case of hyperpigmented MF in a 72-year-old dark-skinned man with a 5-year history of progressive, widespread poikilodermatous patches and thin plaques on the back and bilateral legs. The patient had been treated for lichen planus pigmentosus for 5 years without significant response to therapy.

ASSESSMENT

Multiple biopsies revealed a band-like lymphoid infiltrate in the dermis, accompanied by intraepidermal lymphocytes, some of which had larger hyperchromatic nuclei. CD4+ T lymphocytes were predominant over CD8+ T-positive cells located along the epidermis, dermoepidermal junction, and in the dermis.

DIAGNOSIS

A diagnosis of hyperpigmented MF was made based on the clinical, histopathological, and immunohistochemical findings.

CONCLUSION

This case report highlights the importance of considering hyperpigmented MF as a differential diagnosis in patients with longstanding lichen planus pigmentosus, particularly when there is a lack of response to therapy.

Hyperpigmented mycosis fungoides: a retrospective and comparative analysis with other subtypes of mycosis fungoides

In this study, the clinicopathologic features and survival outcomes of patients with hyperpigmented MF from a single tertiary referral center database were retrospectively evaluated. Hyperpigmented MF accounted for 10.9% (14/128) of all MF cases. The mean age at diagnosis was 46.9 years, and the female-to-male ratio was 1:1.3. Concurrent hypopigmented, ichthyosiform, and poikilodermatous lesions were detected in 21.4%, 14.3%, and 14.3% of the patients, respectively. Histopathologically, most patients (85.7%) showed interface change with pigment incontinence. Double negative (CD4- and CD8-) immunophenotypes were more frequent in patients with hyperpigmented MF (25%) than in those with other MF subtypes (9.8%). Most patients (85.7%) had early-stage disease at diagnosis. The survival outcomes did not differ significantly between hyperpigmented and other MF subtypes. In conclusion, hyperpigmented MF often accompanies other atypical MF variants and is frequently associated with atypical immunophenotypes. The outcomes of hyperpigmented MF are comparable to those of other MF subtypes.

[Treatment of pigmentation disorders in association with systemic diseases]

Pigmentation disorders are a frequent skin problem and incorporate a broad spectrum of diseases, caused by an abnormal melanin pigmentation or also non-melanin pigmentation of the skin. Both hypermelanosis and hypomelanosis can be hereditary or acquired. This article summarizes the treatment approaches that are used in the majority of acquired pigmentation disorders of the skin. The following forms of hypermelanosis are addressed: lentiginosis, hyperpigmentation due to endocrine disorders or other systemic diseases, drug-induced hyperpigmentation. Acquired hypomelanoses include postinflammatory hypomelanosis, chemical depigmentation, idiopathic guttate hypomelanosis and punctate leucoderma. With reference to non-melanin pigmentation, the exogenous pigmentation due to chemicals, metals and drug exposure are discussed. The treatment is primarily based on finding the cause of the alterations to the pigment. The affected area, age and ethnic origin are also important factors. The spectrum of therapeutic options is broad: topical agents, chemical peeling, systemic agents, laser and light-based treatment. As some of these treatment procedures can have side effects, the availability of a protocol that contains information on the drug concentration, dose, parameters for laser treatment and the number of sessions is important. For every disorder the specific dermatological treatment is presented even when some pigmentation alterations that occur in association with systemic diseases, are cured by the treatment of the primary disease. Most diseases are exacerbated by exposure to UV light. Therefore, sun protection is recommended and a cosmetic coverage is indicated.