Comparison of clinicopathological characteristics between T-cell prolymphocytic leukemia and peripheral T-cell lymphoma, not otherwise specified

Does a subset of mature T-cell leukemias with features akin to T-cell prolymphocytic leukemia but lacking rearrangement of the TCL1 represent peripheral T-cell lymphoma, NOS in a leukemic phase?

In the current WHO classification, a T-cell prolymphocytic leukemia (T-PLL) diagnosis requires lymphocytosis of >5 × 109/L, evidence of monoclonality, and TCL1A or MTCP1 rearrangement. However, the 2019 consensus document suggested that in the absence of rearrangement of TCL1-family, the presence of abnormalities involving chromosome 11 (11q22.3; ATM), chromosome 8 (idic(8)(p11), t(8;8), trisomy 8q), 5, 12, 13, 22, or a complex karyotype, as well as involvement specific sites (e.g., splenomegaly, effusions) would suffice for a diagnosis of T-PLL. We present a patient diagnosed with T-PLL with MTCP1 rearrangement who was successfully treated with alemtuzumab followed by consolidative allogeneic unrelated donor stem cell transplantation. Eight years later, the patient presented with inguinal lymphadenopathy with features more akin to peripheral T-cell lymphoma, NOS (PTCL, NOS) of the GATA3 subtype, and there was no evidence of peripheral blood involvement. However, the lymphoma cells were clonally related to those at presentation. Currently, literature on T-PLL-like cases lacking the rearrangement of TCL1A is limited, and the possibility of whether a proportion of such cases could represent PTCL, NOS (with leukemic involvement) needs consideration.

What is new in the 5th edition of the World Health Organization classification of mature B and T/NK cell tumors and stromal neoplasms?

The classification of tumors is essential in the diagnosis and clinical management of patients with malignant neoplasms. The World Health Organization (WHO) provides a globally applicable classification scheme of neoplasms and it was updated several times. In this review, we briefly outline the cornerstones of the upcoming 5th edition of the World Health Organization Classification of Haematolymphoid Tumours on lymphoid neoplasms. As is adopted throughout the 5th edition of the WHO classification of tumors of all organ systems, entities are listed by a hierarchical system. For the first time, tumor-like lesions have been included in the classification, and modifications of nomenclature for some entities, revisions of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities are presented along with mesenchymal lesions specific to the stroma of lymph nodes and the spleen. In addition to specific outlines on constitutional and somatic genetic changes associated with given entities, a separate chapter on germline predisposition syndromes related to hematologic neoplasms has been added.

A Rare Case of CD4 Positive Cytotoxic PTCL, NOS With Leukemic Presentation

Peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS) is a relatively rare mature T-cell lymphoma that cannot be categorized under any of the well-defined category. This type of aggressive lymphoma mostly involves the lymph nodes, though any other organ can be affected. Leukemic presentation is extremely rare. No case report of isolated leukemic presentation was found after detail literature search. Herein we present a case of PTCL, NOS with leukemic presentation.

T-Cell Prolymphocytic Leukemia: Diagnosis, Pathogenesis, and Treatment

T-cell prolymphocytic leukemia (T-PLL) is a rare and aggressive neoplasm of mature T-cells. Most patients with T-PLL present with lymphocytosis, anemia, thrombocytopenia, and hepatosplenomegaly. Correct identification of T-PLL is essential because treatment for this disease is distinct from that of other T-cell neoplasms. In 2019, the T-PLL International Study Group (TPLL-ISG) established criteria for the diagnosis, staging, and assessment of response to treatment of T-PLL with the goal of harmonizing research efforts and supporting clinical decision-making. T-PLL pathogenesis is commonly driven by T-cell leukemia 1 (TCL1) overexpression and ATM loss, genetic alterations that are incorporated into the TPLL-ISG diagnostic criteria. The cooperativity between TCL1 family members and ATM is seemingly unique to T-PLL across the spectrum of T-cell neoplasms. The role of the T-cell receptor, its downstream kinases, and JAK/STAT signaling are also emerging themes in disease pathogenesis and have obvious therapeutic implications. Despite improved understanding of disease pathogenesis, alemtuzumab remains the frontline therapy in the treatment of naïve patients with indications for treatment given its high response rate. Unfortunately, the responses achieved are rarely durable, and the majority of patients are not candidates for consolidation with hematopoietic stem cell transplantation. Improved understanding of T-PLL pathogenesis has unveiled novel therapeutic vulnerabilities that may change the natural history of this lymphoproliferative neoplasm and will be the focus of this concise review.

Mature T-Cell leukemias: Challenges in Diagnosis

T-cell clones can frequently be identified in peripheral blood. It can be difficult to appreciate whether these are benign and transient or whether they signify a clonal disorder. We review factors that aid in understanding the relevance of T-cell clones. Conversely, obvious pathological T-cell clones can be detected in blood, but there is uncertainty in how to categorize this clonal T cell population, thus, we adopt a multidisciplinary review of the clinical features, diagnostic material and radiology before making the diagnosis. In this review we shall discuss some of these challenges faced when diagnosing mature T-cell leukemias.

An unusual case of T-cell prolymphocytic leukemia mimicking a cutaneous vasculitis

T-cell prolymphocytic leukemia (T-PLL) is an aggressive post-thymic T-cell malignancy, which accounts for 2% of mature lymphocytic leukemias in adults. Though typically presenting with a brief history of B symptoms, hepatosplenomegaly, and marked lymphocytosis, erythematous or nodular skin rashes involving the trunk or limbs may be seen in 25% to 30% of patients, as well as a purpuric rash in a periorbital distribution. Cutaneous involvement typically presents in the context of patients with an established history of T-PLL, but it can less frequently present as an initial symptom heralding the diagnosis. An unusual case of T-PLL is described, presenting initially as palmoplantar ulcerated nodules with an initial biopsy suggestive of perniosis, followed by rapid progression of dark violaceous and bright red papules throughout the body after initiation of Obinutuzumab. The diagnosis of T-PLL was subsequently fully supported by the clinical, laboratory, cytologic, and immunophenotypic findings. This case highlights the importance of a multidisciplinary team approach to address such rare and atypical presentations.

T-cell Prolymphocytic Leukemia, Cerebriform Variant

T-cell prolymphocytic leukemia (T-PLL) is a very rare and aggressive lymphoproliferative disorder. We present a 70-year-old man with complaints of fatigue, low urinary output, and peripheral edema for one month. Objectively, he presented diminished respiratory sounds bilaterally and peripheral edema. Analytical study revealed mild anemia and mild lymphomonocytosis, acute kidney injury, and urinalysis with proteins, leukocytes, erythrocytes, and cylinders. Chest radiography was consistent with pleural effusion. Subsequent study showed new onset of thrombocytopenia with a progressive increase of lymphocytosis, in association with inguinal adenopathies and splenomegaly. Immunophenotypic study of peripheral blood and lymph node biopsy were compatible with the diagnosis of T-PLL. Negative serology for human T-cell lymphotropic virus type 1 (HTLV-1) excluded adult T-cell leukemia. Progressive changes in the peripheral blood smear were seen, finally showing the presence of lymphocytes with a cerebriform nucleus, revealing this variant. There was a rapid catastrophic progression, spontaneous tumor lysis syndrome, and death.

A distinct subtype of Epstein-Barr virus-positive T/NK-cell lymphoproliferative disorder: adult patients with chronic active Epstein-Barr virus infection-like features

The characteristics of adult patients with chronic active Epstein-Barr virus infection are poorly recognized, hindering early diagnosis and an improved prognosis. We studied 54 patients with adult-onset chronic active Epstein-Barr virus infection diagnosed between 2005 and 2015. Adult onset was defined as an estimated age of onset of 15 years or older. To characterize the clinical features of these adults, we compared them to those of 75 pediatric cases (estimated age of onset <15 years). We compared the prognosis of adult-onset chronic active Epstein-Barr virus infection with that of patients with nasal-type (n=37) and non-nasal-type (n=45) extranodal NK/T-cell lymphoma. The median estimated age of onset of these lymphomas was 39 years (range, 16–86 years). Compared to patients with pediatric-onset disease, those in whom the chronic active Epstein-Barr virus infection developed in adulthood had a significantly decreased incidence of fever (P=0.005), but greater frequency of skin lesions (P<0.001). Moreover, hypersensitivity to mosquito bites and the occurrence of hydroa vacciniforme were less frequent in patients with adult-onset disease (P<0.001 and P=0.0238, respectively). Thrombocytopenia, high Epstein-Barr virus nuclear antigen antibody titer, and the presence of hemophagocytic syndrome were associated with a poor prognosis (P=0.0087, P=0.0236, and P=0.0149, respectively). Allogeneic hematopoietic stem cell transplantation may improve survival (P=0.0289). Compared to pediatric-onset chronic active Epstein-Barr virus infection and extranodal NK/T-cell lymphoma, adult-onset chronic active Epstein-Barr virus infection had a poorer prognosis (P<0.001 and P=0.0484, respectively). Chronic active Epstein-Barr virus infection can develop in a wide age range, with clinical differences between adult-onset and pediatric-onset disease. Adult-onset chronic active Epstein-Barr virus infection is a disease with a poor prognosis. Further research will be needed.

Clinicopathological features of cryptococcal lymphadenitis and a review of literature

Cryptococcosis is an invasive fungal infection in immunocompromised patients. The clinicopathological characteristics of cryptococcal lymphadenitis are not well known. We analyzed three cases of cryptococcal lymphadenitis and compared their characteristics with those in previous reports. Two patients were human immunodeficiency virus (HIV) carriers, and one patient was a human T-cell leukemia virus type-1 (HTLV-1) carrier. The age of the HTLV-1 carrier with cryptococcosis was much higher than that of the HIV-1 carriers. CD4-positive cell counts in peripheral blood were 5.8/μL (Case 1) and 79.9/μL (Case 2) in the HIV carriers and 3285/μL in the HTLV-1 carrier (Case 3). According to flow cytometric analysis of the lymph nodes of Cases 1, 2, and 3, 50.0%, 87.1%, and 85.9%, respectively, of the T-cells were CD3; 9.8%, 16.3%, and 75.8%, respectively, were CD4; and 35.5%, 77.3%, and 10.2%, respectively, were CD8. Cryptococcus neoformans was detected in tissue culture in all patients. Although gelatinous lesions and numerous fungal cocci were observed in the two HIV patients, the granuloma formation was small. Gelatinous formation and granuloma formation were observed in the HTLV-1 carrier. Necrosis was observed in all cases. In previous reports, granuloma formation, epithelioid cells, and necrotic lesions were observed in most cases. Most of the patients were also immunosuppressed. However, no HTLV-1 carrier was detected. In conclusion, lymphadenopathy in a HTLV-1 carrier may suggest the presence of cryptococcal lymphadenitis. The frequency of cryptococcosis in HTVL-1 carriers may increase with increase in the long-term survival rate of HTLV-1 carriers.