Pincus, Laura B.

ImportanceThere is a knowledge gap about subcutaneous panniculitis-like T-cell lymphoma (SPTCL) owing to its rarity and diagnostic difficulty, resulting in an absence of well-documented large case series published to date.ObjectiveTo generate consensus knowledge by a joint multi-institutional review of SPTCL and related conditions.Design, Setting, and ParticipantsThis retrospective clinical and pathological review included cases initially diagnosed as SPTCL at 6 large US academic centers. All cases were reviewed by a group of pathologists, dermatologists, and oncologists with expertise in cutaneous lymphomas. Through a process of group consensus applying defined clinical and pathological diagnostic criteria, the cohort was classified as (1) SPTCL or (2) adipotropic lymphoproliferative disorder (ALPD) for similar cases with incomplete histopathological criteria for SPTCL designation.ExposuresCases of SPTCL diagnosed between 1998 and 2018.Main Outcomes and MeasuresThe main outcome was disease presentation and evolution, including response to therapy, disease progression, and development of hemophagocytic lymphohistiocytosis.ResultsThe cohort of 95 patients (median [range] age, 38 [2-81] years; female-to-male ratio, 2.7) included 75 cases of SPTCL and 20 cases of ALPD. The clinical presentation was similar for both groups with multiple (61 of 72 [85%]) or single (11 of 72 [15%]) tender nodules mostly involving extremities, occasionally resulting in lipoatrophy. Hemophagocytic lymphohistiocytosis (HLH) was only observed in SPTCL cases. With a mean follow-up of 56 months, 60 of 90 patients (67%) achieved complete remission with a median (range) of 3 (1-7) cumulative therapies. Relapse was common. None of the patients died of disease progression or HLH. Two patients with ALPD eventually progressed to SPTCL without associated systemic symptoms or HLH.Conclusions and RelevanceIn this case series of patients initially diagnosed as having SPTCL, results showed no evidence of systemic tumoral progression beyond the adipose tissue. The SPTCL experience in this study confirmed an indolent course and favorable response to a variety of treatments ranging from immune modulation to chemotherapy followed by hematopoietic stem cell transplantation. Morbidity was primarily associated with HLH.

This pathology PILOT study aims to define the role and feasibility of centralized pathology review in a cohort of 75 patients from different centers in the United States and Europe using digital slide scanning. The pathologic material from 75 patients who had been diagnosed with mycosis fungoides/Sézary syndrome and were clinically staged as IIb or above was retrieved from 11 participating centers. Each pathology reviewer was provided with the pathologic diagnosis (by the referring pathologist), and the following list of histopathologic criteria (presence or absence) from the initial report: epidermotropism, folliculotropism (FT), large cell transformation, syringotropism, and granulomas. Patients with advance stage were selected for this study as this is a population where there is significant variability in the diagnosis of pathologic prognostic and predictive biomarkers. The slides were digitally scanned with an Aperio scanner and consensus review of cases occurred when major or minor discrepancies between the referral diagnosis and central pathology review occurred. Among the 75 cases, 70 (93.3%) had a final consensus diagnosis between the 3 central review pathologists. The overall agreement between the consensus review and the referring pathologist was 60%. The overall agreement was also higher between the reviewers and consensus review, compared with the referring pathologist and consensus. 65.3% of cases had some type of discrepancy (major or minor) between the outside and consensus review. Major discrepancies were seen in 34 of 73 cases (46.6%; 73 cases indicated a yes or no response). Minor discrepancies were seen in 32 of 75 (42.7%) of cases. Most of the major discrepancies were accounted by a difference in interpretation in the presence or absence of large cell transformation or FT. Most minor discrepancies were explained by a different interpretation in the expression of CD30. We found digital slide scanning to be a beneficial, reliable, and practical for a methodical approach to perform central pathology review in the context of a large clinical prospective study.