Primary Cutaneous Lymphomas; A review of a rare but diverse cutaneous tumour.
Introduction: Primary cutaneous lymphomas (PCLs) are rare tumours accounting for 18% of cases of extra nodal non Hodgkin's lymphomas (NHL). PCLs are potential differentials in cases of cutaneous malignant skin tumours that may pose diagnostic difficulties to the Clinicians and Pathologists. Paucity of data exists in our own environment in particular and in Nigeria in general. This article serves to review available existing literature with the goal of creating the awareness to Pathologists and Clinicians (especially Dermatologist) of its existence and a possible encounter in the line of duty.
Literature review: Primary CLs are rare tumours. Most previous studies on malignant skin tumours in Nigeria did not report a case of CLs. This is unlike the report from Lagos, Nigeria where CLs have been reported. Cutaneous T- cell lymphomas (CTCLs) makes up about 2/3rd of the PCLs. Mycosis fungoides is the most common CTCLs while Marginal zone B-cell lymphoma and Follicular centre lymphoma are the most common subtypes of Cutaneous B- cell lymphomas (BTCLs). The aetiology PCLs is largely unknown. The CTCLs are predominantly seen in males while BTCLs show no sexual predilection except in primary cutaneous follicular centre lymphoma that has a slight female predilection. Their clinical presentation is non- specific and varies from patch, to plaques to nodules. They also exhibit variable histologic, immunophenotypic, cytogenetic, and molecular features.
Conclusion: Despite being rare, we should not foreclose the possibility of finding isolated cases of CLs in our environment. Large population and molecular tools are necessary to elucidate the aetiology of the diverse spectrum of CLs. Institutional/hospital based studies are invaluable means in the gathering of data, especially for rare tumours like CLs.
Key words: Primary cutaneous lymphomas, Cutaneous T- and B- cell lymphomas, Mycosis Fungoides, Sezary Syndrome, Marginal zone B-cell.