Diagnosis of gamma/delta mycosis fungoides requires longitudinal clinical observation

Updated Classification of Cutaneous Lymphoma

The International Consensus Classification (ICC) of myeloid and lymphoid neoplasms follows the precedent set in the Revised European-American lymphoma classification for modern lymphoma classifications by defining specific diseases on the basis of all the available morphologic, immunophenotypic, genetic, and clinical findings. Primary cutaneous lymphomas exhibit a broad range of clinical behavior ranging from lesions which spontaneously regress to those which run an aggressive, often fatal course. Accurate separation of entities is therefore essential for prognostication and to ensure appropriate treatment is administered. However, despite marked differences in clinical course, many subtypes of primary cutaneous lymphoma exhibit remarkably similar, often overlapping, and sometimes indistinguishable pathologic features. While molecular analysis has furthered our understanding of some of these disease entities, it does not yet facilitate robust distinction. Thus, clinical correlation retains a central role in both the diagnosis and classification of primary cutaneous lymphoma. This review aims to draw attention to problem areas in differential diagnosis and hopefully offer some practical suggestions for resolving difficult cases. It will also highlight recent advances in the field and discuss how they reinforce the current classification system and how they might impact of future classifications and treatment strategies.

Rapidly Progressive Primary Cutaneous Gamma Delta T-Cell Lymphoma With FYN Gene Alteration

ABSTRACT

Primary cutaneous gamma delta T-cell lymphoma (PCGDTCL) is a rare type of non-Hodgkin lymphoma accounting for <1% of primary cutaneous T-cell lymphomas. The exact cause of PCGDTCL is not known, however, it is thought that chronic antigen exposure in the skin may lead to immune dysregulation at the site, resulting in abnormal proliferation of mature, post-thymic cytotoxic gamma delta T cells. Mutations are the most common genetic alteration seen in PCGDTCL, while structural abnormalities such as gene fusions are not common. We report a case of PCGDTCL with atypical immunophenotypic features, including expression of CD5 with lack of cytotoxic marker expression, and a structural alteration leading to FYN deletion at exon 8. Recently, it was described that a deletion of the area between FYN exon 8 and TRAF3IP2 intron 2 results in a novel FYN::TRAF3IP2 fusion in peripheral T-cell lymphoma, not otherwise specified. We describe our patient's clinical course, differential diagnosis, and potential implications of FYN deletion on disease pathogenesis. To our knowledge, this is the first report of an FYN structural alteration to be described in PCGDTCL.

A Case of CD4 + T-Cell Lymphoma With Gamma-Delta Phenotype, Incidentally Manifesting in a Wound Debridement Sample

ABSTRACT

We report an 85-year-old male patient with a medical history significant for psoriasis who presented with a thigh wound that expanded slowly over the course of 9 months. The patient was previously treated with amputation of hand digits for osteomyelitis. Histologic examination of the tissue sample revealed a broad ulceration with large areas of necrosis extending into the subcutis. The edge of the specimen also revealed a nodular lymphoid infiltrate in the subcutaneous adipose tissue composed of atypical cells. These cells were only positive for CD3, CD4, and T-cell receptor (TCR) delta stains . The Ki-67 proliferation index of tumor cells was about 70%. The tumor cells were negative for CD30, CD8, CD56, TCR BF1, granzyme, TIA1, CD123, and Epstein-Barr encoding region (EBER)-ish stains. A diagnosis of gamma-delta T-cell lymphoma was made. Further imaging showed regional lymphadenopathy. The patient was started on mini-CHOP and filgrastim; however, the patient died within 1 month after the diagnosis. This is an interesting case of gamma-delta T-cell lymphoma that was incidentally diagnosed on a chronic wound. In addition, it showed a CD4 + , CD8 - phenotype that is exceedingly rare for T-cell lymphomas with gamma-delta phenotype.

Early Organ Metastasis in Granulomatous Mycosis Fungoides: A Systematic Review

BACKGROUND

Granulomatous mycosis fungoides (GMF) is a rare form of cutaneous T-cell lymphoma characterized by a granulomatous inflammatory infiltrate.

OBJECTIVE

The impact of granulomatous inflammation on the prognosis of the disease remains controversial as there have been both favorable and unfavorable outcomes documented.

METHODS

We performed a systematic review of 116 GMF cases previously described in the literature.

RESULTS

In contrast to the classic Alibert-Bazin type of mycosis fungoides (MF), cutaneous lesions in GMF tend to involve distal extremities (lower legs, feet, hands) early in the disease course. In the literature, 30% of GMF patients developed organ metastasis, most frequently to the lung. The median time to stage progression was 25 months.

CONCLUSION

GMF is an aggressive form of MF. Therefore, screening for distant metastases should be considered at presentation and repeated during follow-up.

Aggressive Cutaneous Lymphomas and Their Mimics

Cutaneous lymphomas encompass a heterogeneous group of neoplasms with a wide spectrum of clinical presentations, histopathologic features, and prognosis. Because there are overlapping pathologic features among indolent and aggressive forms and with systemic lymphomas that involve the skin, clinicopathologic correlation is essential. Herein, the clinical and histopathologic features of aggressive cutaneous B- and T-cell lymphomas are reviewed. Indolent cutaneous lymphomas/lymphoproliferative disorders, systemic lymphomas, and reactive processes that may mimic these entities are also discussed. This article highlights distinctive clinical and histopathologic features, increases awareness of rare entities, and presents new and evolving developments in the field.

The significance of epidermal involvement in primary cutaneous gamma/delta (γδ) T-cell lymphoma: A systematic review and meta-analysis

BACKGROUND

Primary cutaneous gamma/delta (γδ) T-cell lymphoma (PCGDTCL) is a rare, aggressive peripheral T-cell lymphoma. There is evidence that patients with epidermotropic PCGDTCL may have an improved prognosis compared with those with only dermal and/or subcutaneous involvement.

METHODS

Systematic review of the literature and application of inclusion criteria yielded 48 manuscripts detailing the cases of 104 patients.

RESULTS

Of the 104 patients, 57 were male (51.4%) and 47 were female (48.5%) Based on provided histopathologic descriptions, 57 cases (54.8%) had no epidermotropism, 47 cases (45.2%) patients demonstrated any degree of epidermotropism, and 25 cases were predominantly epidermotropic (25/104, 24%). Five-year overall survivals for patients with no epidermotropism, any epidermotropism, and predominantly epidermotropic presentation were 32.8%, 28.9%, and 40.0%, respectively (p = 0.40). The most commonly performed immunohistochemical markers were CD3, CD4, CD8, CD5, CD7, CD30, CD56, TCR beta, TCR γ, and TCR δ. There was no statistically significant difference in immunophenotype between groups. Lesion morphology was described in the majority of cases (85/104, 80.9%); most cases presented as a combination of nodules, plaques, and tumors (77.4%). Several cases had more atypical presentations, including "mycosis-fungoides-like" and ulcerated.

CONCLUSION

In PCGDTCL, neither epidermotropism nor predominantly epidermotropic phenotype predict a better prognosis. In addition, the case report literature in dermatology and dermatopathology is rich and highly valuable.