Primary Cutaneous T Cell Lymphoma (Gamma Delta subtype): Beyond the Abstract

Non-mycosis fungoides cutaneous T cell lymphomas are uncommon. The rarer sub-types are not well studied due to the rarity of the condition and also paucity of data. Peripheral T Cell Lymphoma involving the skin as primary manifestations are uncommon. Primary cutaneous gamma-delta T cell Lymphoma is one of the rare sub-type delineated in the WHO-EORTC classification as a provisional entity. [1]

Treatment of these entities is difficult due to paucity of evidence and dismal outcome of conventional therapies. Many of them are resistant to multi-agent chemotherapy and radiotherapy. As shown in the case report, the patient responded fairly well initially to chemotherapy but relapses aggressively very early on. 

Newer novel therapies might hold promise for these rare entities. Histone deacetylase inhibitors (HDACi) have long been used in cutaneous T-cell lymphomas with varying degrees of success. The more aggressive forms of Peripheral T Cell Lymphomas however usually do poorly with single agent HDACi. Checkpoint inhibitors is another emerging therapy with great promise after initial encouraging results shown in lymphoma trials.[2] Combination of these novel therapies with or without conventional multi-agent chemotherapy would likely be the way forward in treating these difficult entities.

However, the non-availability of these newer agents to many of the treating doctors worldwide is a big issue. Absence of trials, the prohibitively high cost of many of these agents as well as difficulty to obtain timely approval and clearance from relevant authorities is real world issues faced daily by many doctors worldwide. 

Establishing a robust and relevant national or regional haematological cancer registry would be a big first step in helping to plan treatment strategies. A regional or national registry that includes these rare diseases can help pool data and maybe, in the future, help regional or national bodies push for better availability of newer expensive treatment with the cooperation of the pharmaceutical industries via clinical trials or patient programmes. 

Written by: Yong Khee Guan, MBBS (Malaya), MRCP (UK) & Chye Chung Gan MBBS (AIMST), MRCP (UK)
Department of Medicine, Hospital Melaka, Melaka, Malaysia

References:
1. Gaulard P, et al. Primary cutaneous peripheral T-cell lymphomas, rare subtypes. WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues 4th Edition. 2008:302-305. 

2. Lesokhin AM, Ansell SM, Armand P, et al. Preliminary results of a phase I study of nivolumab (BMS-936558) in patients with relapsed or refractory lymphoid malignancies [abstract]. Blood 2014;124(21). Abstract 291

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