CD8+ mycosis fungoides: A wolf in sheep’s clothing?

Sir, CD8+ mycosis fungoides (MF) is a rare form of MF with an indolent course. Herein, we report a rare case of CD8+ fungoid mycosis preceded by lymphomatoid papulosis type D with an aggressive course. A 36-year-old female presented with several papular lesions on the trunk and extremities with a relapsing–remitting course. Histopathology and an immunohistochemical study confirmed CD8-positive lymphomatoid papulosis type D and methotrexate at 25 mg/week was initiated. After a temporary clinical improvement, the lesions worsened, became infiltrated, and grouped as vaguely annular and angular patches with serpiginous borders (Fig. 1). A second scalp biopsy was performed and a diagnosis of CD8+ MF was established. An extension workup was normal, and MF was classified as stage IB. PUVA therapy was started with acitretin at 25 mg/day. After four weeks from the beginning of treatment, the patches completely disappeared but with the concomitant appearance of four subcutaneous tumors. The evolution was spectacular in fifteen days, with the tumors rapidly increasing in size, becoming ulcerative and necrotic, and one being localized in the left cervical area compressing the upper respiratory tract (Fig. 2). A subsequent biopsy revealed massive epidermal and dermal large cell infiltration (Fig. 3a); the tumor cells were positive for CD3, CD8, and CD7 (Fig. 3b) and negative for CD4, CD5, CD3, CD2, and CD30. Antigen Ki-67 was expressed by more than 80% of T-cells (Fig. 3c). A cerebral and thoraco-abdominal CT scan revealed multiple axillary lymph nodes with hypermetabolism on a PET scan. An osteomedullar biopsy was normal, and lactate dehydrogenase (LDH) was increased to 358 U/L. Chemotherapy was performed, but the patient died after two cycles of CHOEP. In contrast to classical CD4+ mycosis fungoides, CD8+ MF is a rare cytotoxic phenotype constituting about 5% of all cases of MF [1]. It belongs to the first group of primary cytotoxic cutaneous lymphomas (PCCL) with a good prognosis, an indolent course, and a slow progression of the lesions over several years [2]. However, rare cases with a more aggressive course have been reported in the literature [3]. The main differential diagnosis of aggressive CD8+ MF is an aggressive epidermotropic cutaneous CD8+ lymphoma that is a rare cutaneous lymphoma with a poor prognosis due to rapid extracutaneous dissemination [4]. The prognosis of the CD8+ subtype of mycosis fungoides (MF) is controversial. More studies are necessary to clarify this subject.

Primary Cutaneous Gamma-Delta T Cell Lymphomas: A Case Series and Overview of the Literature

Primary cutaneous gamma-delta T cell lymphomas (PCGDTCLs) are rare and aggressive cutaneous malignancies that have been diagnostically challenging for dermopathologists and clinicians since their first published descriptions in 1991. Since then, the availability of immunostaining for T cell receptors γ and δ in formalin-fixed paraffin-embedded samples has greatly increased our knowledge of the gamma-delta phenotype by showing that it may also be present in the context of indolent entities, such as mycosis fungoides (MFs) and lymphomatoid papulosis, and this has raised questions concerning its diagnostic and prognostic implications. We here describe the histological and clinical differences between the dermo-epidermal and subcutaneous sub-groups of PCGDTCL observed in a cohort of 20 patients attending a single experienced centre, with particular focus on cases with an MF-like presentation, which are still less well defined than those of classic MF.

Genomic Analysis of Cutaneous CD30-Positive Lymphoproliferative Disorders

Primary cutaneous CD30+ T-cell lymphoproliferative disorders (CD30+ LPD) are the second most common cutaneous lymphomas. According to the World Health Organization (WHO), CD30+ LPD include primary cutaneous anaplastic large cell lymphoma (pcALCL) and lymphomatoid papulosis (LyP) as well as borderline lesions. pcALCL and LyP is thought to represent two ends of a spectrum of diseases that have different clinical presentations, clinical courses, and prognoses in their classic forms, but share the same histology of medium to large CD30+ atypical lymphoid cell infiltrates. Because the behavior of these entities is different clinically and prognostically, we aim to search for oncogenic genomic variants using whole exome sequencing (WES) that drive the development of LyP and pcALCL. Clinical information, pathology, immunohistochemistry, and T-cell rearrangements on six cases of LyP and five cases of pcALCL were reviewed to confirm the rendered diagnosis prior to WES of all specimens. All cases of CD30 LPD had recurrent mutations in at least one of the epigenetic modifying genes, with the most frequent mutations found in the mixed lineage methyltransferase family involved in the methylation of H3K4: CREBBP (27%), KMT2A (36%), KMT2D (36%), SETD2 (27%), and SMARCA4 (27%) (Figure). Within the JAK/STAT pathway, mutations of STAT3 were observed in 2 cases of pcALCL (n=2, 18%), STAT5B in one case of LyP (n=1, 9%) and JAK1 mutation in one case of LyP(n=1, 9%). Lastly, mutations were also identified in the T-cell signaling pathway. 3/5 cases of pcALCL demonstrated loss of function mutations in EOMES, a T-box transcription factor important in lymphocyte development. We had two cases of C-ALCL and one case of LyP with NOTCH1 mutations supporting the importance of this gene in T-cell lymphomas. TP53 mutations and copy number loss is more characteristic of aggressive lymphomas and these abnormalities were absent in pcALCL and LyP and may explain the indolent nature of CD30+ LPD. While the JAK/STAT pathway, T-signaling, and epigenetic alterations possibly play a role in the pathogenesis of these diseases, genes involved in cell-cycle control and apoptosis (ie. TP53) that are characteristic of more aggressive diseases were not identified. Extending this investigation to a larger number of samples will allow us to detect additional mutations that may help distinguish between CD30+ LPDs of LyP and pcALCL as well as other histologic mimics such as systemic ALCL and large cell transformation of MF. Figure 1 Figure 1. Disclosures Abdulla: Caris Life Licenses: Current Employment. Zain: Kiyoaw Kirin, Secura Bio, Seattle Genetics: Honoraria; Secura Bio, DaichiSankyo, Abbvie: Research Funding; Secura Bio, Ono , Legend, Kiyowa Kirin, Myeloid Therapeutics Verastem Daichi Sankyo: Consultancy.

Case Report: Contrasting BCL2 Upregulation With Venetoclax in a Case of Refractory Lymphomatoid Papulosis and Progressive Chronic Lymphocytic Leukemia

A 57-year-old man affected by high-risk progressive chronic lymphocytic leukemia (CLL), primary resistant to first-line chemoimmunotherapy, developed a type A lymphomatoid papulosis (LyP) during a second progression of CLL. The two blood tumor entities were clonally unrelated. LyP presented with a diffuse (>90% body surface area) cutaneous rash and was characterized by intensely pruriginous dusky nodules (n = 10) and red flat-topped papules (n = 60). No response to topical corticosteroids and psoralen plus ultraviolet A (PUVA) phototherapy was observed. In order to effectively treat progressive TP53-mutated CLL, the potent BCL2 inhibitor, venetoclax, was initiated with no treatment-related complications. While CLL only achieved a partial response, a complete remission of LyP-associated cutaneous rash and of the intractable pruritus was obtained within 2 months from venetoclax initiation. BCL2 immunostaining of the original cutaneous specimen showed a strong over-expression of the anti-apoptotic protein, restricted to CD30+ lymphoid cells and reactive microenvironment. At 12 months follow-up, the patient is still in complete remission of LyP. Our findings underline the probable pathogenic role of BCL2 in LyP and the potential therapeutic efficacy of venetoclax for the treatment of this primary cutaneous CD30+ lymphoproliferative disorder, especially in the setting of severe and refractory disease.