Mycosis Fungoides

Is it mycosis fungoides? A comprehensive guide to reaching the diagnosis and avoiding common pitfalls

Mycosis Fungoides (MF) is known as 'the great mimicker' due to its capacity to emulate several dermatoses, both in the clinic and on histology. This often leads to the diagnosis being missed or delayed, which consequently leads to poorer prognosis. For a timely diagnosis, it is crucial that the physician is aware of the various clinical and histological presentations of MF, as well as the proper diagnostic protocols. In the current review, we concisely encapsulate all the variants of MF as well has the conditions it mimics clinically and histologically. Through this, we aim to provide clinicians with a holistic picture of MF and help them determine when to suspect this disease and steps to take in order to nail the diagnosis.

Cutaneous Metastases: A Review and Diagnostic Approach to Tumors of Unknown Origin

CONTEXT.—

Cutaneous metastases from a distant malignancy are a diagnostic challenge for pathologists. Secondary involvement of the skin by a metastatic process portends a much worse clinical prognosis than any primary cutaneous malignant mimickers. Immunohistochemical staining methods continue to evolve and are of paramount importance in diagnosis.

OBJECTIVE.—

To review the clinical, histopathologic, and immunohistochemical staining patterns for commonly encountered entities and discuss potential pitfalls in diagnosis. A practical guide useful in approaching cutaneous metastases of unknown primary is outlined.

DATA SOURCES.—

An extensive search and review of literature in PubMed was performed, processed, and condensed.

CONCLUSIONS.—

Cutaneous metastases have broad histopathologic patterns. They are nearly always dermal based, with an overall foreign appearance. They can be single papules/nodules or multiple in number, mimicking an inflammatory or infectious process. Ultimately, immunohistochemistry remains an essential diagnostic tool, and clinical correlation is paramount in the workup of these entities.

Mycosis Fungoides Involving the Dorsal Tongue

Mycosis fungoides (MF) is a rare cutaneous T-cell lymphoma (CTCL) which can cause significant morbidity. During the disease course, it classically will progress through three clinical stages in the skin: patch-, plaque-, and tumor-stage. The early stages exhibit various histopathological mimics that often lead to misdiagnosis. It rarely affects the oral cavity. Oral MF is historically associated with poor prognosis. We present a rare case of MF afflicting the dorsal tongue and extremities of a 72-year-old male.

An uncommon diagnosis for a recurrent erythematous patch in a paediatric patient

A 14-year-old girl presented with a circular erythematous patch over the left buttock for approximately 10 years, with ongoing ulceration and papules developing over the last 4 years. Punch biopsies were taken within and above the patch for diagnosis. Both revealed marked inflammatory infiltrates with atypical, irregular lymphocytes and increased mitosis. Immunostaining revealed CD8 positivity and a pan T helper cell phenotype. T cell receptor gene rearrangement analysis showed T cell clonality in both biopsies. These findings were consistent with mycosisfungoides and associated lymphomatoid papulosis. Both are rare conditions but have been associated in 5%-20% of cases. A definitive association has not yet been established; however, T cell monoclonality shows 50%-60% share a common origin. Management options are extensive with no one treatment showing superiority. Our patient received low-dose radiotherapy with good outcomes, but subsequently required further radiotherapy.