CSF3R T618I mutated chronic myelomonocytic leukemia: A proliferative subtype with a distinct mutational profile.

Chronic myelomonocytic leukemia (CMML) is a clonal myeloid neoplasm characterized by sustained monocytosis and mutations in TET2, ASXL1, SRSF2, SETBP1, NRAS, and KRAS. We describe a rare case of CSF3R T618I mutated CMML that has a proliferative phenotype, myelodysplasia, and additional mutations in ASXL1, SETBP1, KRAS, and PTPN11. Comparing the clinicopathologic features of this case to previously reported cases of CSF3R T618I mutated CMML and CSF3R non-T618I mutated CMML, CSF3R T618I seems to define a unique proliferative subtype of CMML with a distinct mutational profile. The diagnostic challenges and molecular pathogenesis associated with this case are also briefly discussed.

Lymphomatoid granulomatosis of the central nervous system (CNS-LYG) posing a management challenge.

Isolated central nervous system lymphomatoid granulomatosis (CNS-LYG) can mimic aggressive glioblastomas. We describe a complex presentation of CNS-LYG coexisting with immune thrombocytopenia successfully managed with rituximab and ultra-low-dose radiation therapy.

A Wandering Missionary's Burden: Persistent Fever and Progressive Somnolence in a Returning Traveler.

Human African trypanosomiasis incidence has declined, but diagnosis remains difficult, especially in nonendemic areas. Our patient presented with fever, progressive lethargy, and weight loss for 5 months and had previously traveled to Ghana and Cameroon but had not been to areas with recently reported African trypanosomiasis. Extensive workup was negative, except for lymphocytic pleocytosis in cerebrospinal fluid; ultimately, a bone marrow aspiration revealed necrotizing granulomatous inflammation with 2 trypanosomes discovered on the aspirate smear, consistent with Trypanosoma brucei. The patient was treated with combination nifurtimox and eflornithine with full recovery.

Combined immune checkpoint blockade and radiotherapy induces durable remission in relapsed natural killer/T-cell lymphoma: a case report and review of the literature.

BACKGROUND: Extranodal natural killer/T-cell lymphoma is a rare, aggressive non-Hodgkin lymphoma that is treated upfront mostly with L-asparaginase containing regimens. Relapsed extranodal natural killer/T-cell lymphoma is associated with a poor prognosis, and there is no established standard of care. CASE PRESENTATION: We report the case of a 72 year-old white male with a distant extranasal relapse of extranodal natural killer/T-cell lymphoma that has been managed successfully with a combination of radiation and immune checkpoint blockade with pembrolizumab. Pseudoprogression with new skin and bone lesions on positron emission tomography imaging was encountered during this Caucasian patient's immunotherapy and was successfully managed with supportive care and continuation of immune checkpoint blockade. CONCLUSIONS: The patient has been in complete clinical, radiologic, and molecular remission for close to 3 years and has not had any immune-related adverse effects. Pseudoprogression is a clinical challenge that can be encountered while patients are treated with immunotherapy, and astute clinical acumen is needed for accurate management. We believe this is the longest duration of response to immune checkpoint blockade in relapsed extranodal natural killer/T-cell lymphoma reported to date in literature. There is a strong biologic rationale in combining radiation with immunotherapy. The optimal timing, dose, and duration of radiation combined with immunotherapy in extranodal natural killer/T-cell lymphoma need to be prospectively evaluated.

Lenalidomide-Associated Secondary B-Lymphoblastic Leukemia/Lymphoma-A Unique Entity.

OBJECTIVES: Autologous stem cell transplant with lenalidomide maintenance therapy has greatly improved the relapse-free and overall survival rates of patients with multiple myeloma but also has been associated with an increased risk of secondary B-lymphoblastic leukemia/lymphoma (B-ALL). METHODS: We report a comprehensive review of the clinicopathologic features of 2 patients with multiple myeloma who developed secondary B-ALL during lenalidomide maintenance. RESULTS: Our observations showed that the disease may initially present with subtle clinical, morphologic, and flow-cytometric findings. The flow cytometry findings in such cases may initially mimic an expansion of hematogones with minimal immunophenotypic variation. Both patients achieved complete remission of secondary B-ALL after standard chemotherapy; however, one patient continues to have minimal residual disease, and the other experienced relapse. Next-generation sequencing of the relapse specimen showed numerous, complex abnormalities, suggesting clonal evolution. CONCLUSIONS: Our findings suggest the need for increased awareness and further study of this unique form of secondary B-ALL.

Tumoral Mimics of Subdural Hematomas: Case Report and Review of Diagnostic and Management Strategies in Primary B-Cell Lymphoma of the Subdural Space.

BACKGROUND: Subdural lymphomas are a rare subtype of primary central nervous system lymphomas that can radiographically mimic epidural blood and pose a diagnostic challenge. They can complicate treatment if not preemptively identified. METHODS: We present a case report of a subdural lymphoma that mimicked a compressive subdural hematoma, and we review the PubMed database for similar cases. RESULTS: A 77-year-old woman presented with a transient left facial droop and what appeared to be a subdural hematoma on computed tomography scan. The patient underwent surgery, during which grossly abnormal solid epicortical adherent tissue was noted instead of the expected appearance of a subdural hematoma. An intraoperative biopsy was suggestive of lymphoma, and the surgery was converted to a craniectomy. Pathology confirmed the diagnosis of extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue. The patient underwent radiotherapy with no complications or recurrence. Magnetic resonance imaging demonstrated complete resolution of the mass at 3 months after treatment, at which time the patient underwent a synthetic cranioplasty. Seven case reports of primary dural lymphomas mimicking subdural blood were found, with variable pathologic subclassifications. CONCLUSIONS: Although rare, a primary dural lymphoma can be mistaken for a subdural hematoma on computed tomography scan. The most common subtype is low-grade extranodal marginal zone lymphomas. It is important to keep these diseases in the differential diagnosis, especially when there is incongruence between imaging and the clinical picture, as earlier detection correlates to a stronger therapeutic response.

Burkitt lymphoma presenting as a mass in the thyroid gland: a clinicopathologic study of 7 cases and review of the literature.

Burkitt lymphoma presenting in the thyroid gland is rare, and only a few cases have been reported. We retrospectively reviewed 7 patients diagnosed with Burkitt lymphoma of the thyroid gland between 2000 and 2015. There were 4 men and 3 women with a median age of 41 years (range, 19-49 years). All patients presented with a rapidly growing neck mass associated with upper airway compression in 5 (71%) patients. Two patients presented with localized (stage I/II) and 5 patients with disseminated (stage III/IV) disease. All cases showed morphologic and immunophenotypic features of Burkitt lymphoma with MYC rearrangement in all 5 cases tested. One case showed evidence of concurrent Hashimoto thyroiditis. Six of 7 patients were treated primarily with rituximab, hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone. One patient was treated primarily with dose-adjusted rituximab, etoposide, prednisolone, vincristine, and cyclophosphamide. At the end of the study period, 5 patients were alive: 4 in complete remission and 1 with persistent disease. Two patients died with persistent disease (median follow-up, 25 months; range, 12-361 months). We conclude that Burkitt lymphoma of the thyroid gland shows clinicopathologic features similar to sporadic Burkitt lymphoma at other anatomic sites, but patients present at an older median age. The clinical course is aggressive with a high frequency of disseminated disease at diagnosis; however, a subset of patients responds well to aggressive chemotherapy.

Clinicopathologic features of CD5-positive nodal marginal zone lymphoma.

OBJECTIVES: To describe the clinicopathologic findings of seven patients with CD5-positive nodal marginal zone lymphoma (NMZL). METHODS: We searched cases of NMZL over a 10-year interval and identified seven cases of CD5-positive NMZL. The clinical, histologic, and immunophenotypic findings of this group were reviewed, and the frequency of dissemination in this group was compared with that of 66 patients with CD5-negative NMZL. RESULTS: Other than CD5 expression, the histologic and immunophenotypic findings were typical of NMZL. Six (86%) of seven patients had lymphadenopathy above and below the diaphragm, and all six patients assessed had bone marrow involvement. In the CD5-negative group, 28 (42%) patients had lymphadenopathy above and below the diaphragm, and 36 (55%) had bone marrow involvement (P = .045 and P = .037, respectively). Six of seven patients were alive at last follow-up, with a median follow-up of 32 months (3-154 months). CONCLUSIONS: CD5 expression in NMZL correlates with a higher frequency of dissemination, but patients have an indolent clinical course and excellent overall survival.