Proliferative Clonal T-Cell Infiltrate Mimicking a Cutaneous T-Cell Lymphoma Arising in Active Regression of Melanoma.

ABSTRACT: Complete melanoma regression is an uncommon phenomenon involving a complex interplay of the tumor microenvironment and host immune response. We report a case of an 84-year-old woman with a history of colon and breast cancers who presented with a right forearm tumor, which was found to be a nodular melanoma; focal features of regression were noted in the biopsy. Approximately 6 weeks later, surgical resection of the site revealed no gross evidence of tumor, and histologic sections showed an extensive lymphoid infiltrate with prominent epidermotropism. Rare residual melanoma cells were present in the dermis, best visualized on immunohistochemical stains. T cells predominated in the infiltrate with an inverted CD4:CD8 ratio at approximately 1:2. There was no appreciable loss of pan‒T-cell antigens. T-cell receptor beta and gamma gene rearrangements were performed by polymerase chain reaction and demonstrated clonality in each assay. Although a synchronous cutaneous T-cell lymphoma was considered, the overall clinicopathologic features are more in line with an exaggerated host immune response leading to near complete regression of the tumor.

B-cell prolymphocytic leukemia: an enduring bona fide entity.

B-cell prolymphocytic leukemia (B-PLL) was recognized as a distinct entity in the fourth edition of the World Health Organization (WHO) classification for hematolymphoid neoplasms (WHO-HAEM4); however, its de novo presentation has been removed from the upcoming 5th edition classification (WHO-HAEM5). We present a case of a 65-year-old man with leukocytosis, fatigue, and no organomegaly by imaging. Bone marrow examination showed a prolymphocytoid population comprising 78% of the marrow elements. After thorough exclusion of other entities by clinical parameters and ancillary methods, we concluded that this case represents a de novo case of B-PLL.

Serum CD64 as a Marker for Chronic Periprosthetic Joint Infection.

Background: Serum cluster of differentiation 64 (CD64) has emerged as a diagnostic test for musculoskeletal infections. The purpose of this study was to evaluate the utility of serum CD64 in diagnosing periprosthetic joint infections (PJIs) compared to conventional markers like white blood count (WBC), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and interleukin-6 (IL-6). Methods: A prospective case-control study on patients undergoing revision hip or knee arthroplasty surgery >6 weeks after their index surgery was performed at a single institution. Whole blood samples were drawn within 24 hours prior to revision surgery for white blood count, ESR, CRP, IL-6, and CD64. Intraoperative cultures were obtained during the revision, and PJI was defined using the major criteria from the 2018 Musculoskeletal Infection Society criteria. Two-sample Wilcoxon rank-sum test and Fisher's exact test were used to determine if there were significant differences in serum laboratory values between patients with and without infection. The sensitivity, specificity, positive predictive value (PPV), negative predictive value, and accuracy of each test were calculated. Results: With an average age of 67 years, 39 patients with 15 revision THAs and 24 TKAs, were included. 19 patients (48.7%) were determined to have PJI. Patients with PJI had significantly higher CD64 (P = .036), CRP (P = .016), and ESR (P = .045). CD64 had the highest specificity (100%) and PPV (100%), moderate accuracy (69.2%), but low sensitivity (37.0%) and negative predictive value (62.5%). Conclusions: Given the high specificity, PPV, and accuracy, CD64 may be an excellent confirmatory test to help diagnose PJI.

Deceiving high-grade cervical dysplasias identified as human papillomavirus non-16 and non-18 types by Invader human papillomavirus assays.

High-grade cervical intraepithelial lesions (HGCINs) are easily diagnosed by established histologic criteria. However, we encountered problematic cases that are difficult to diagnose because features intermediate between dysplasia and metaplasia are present. p16 and Ki-67 immunostains proved HGCIN in these difficult and unusual cases. Because these are unusual cases of cervical dysplasia, we decided to type the human papillomavirus (HPV) using the Invader HPV test with analyte-specific reagents developed by Third Wave Technologies (Madison, WI, USA) (a new HPV screening assay applicable to tissue and amenable to rapid, sensitive, and specific detection of 14 high- to intermediate-risk HPV types) and a panel of immunostains. Results of these difficult cases are compared with classic HGCIN cases. We searched our pathology files over a period of 16 months for high-grade squamous intraepithelial lesion, cervical intraepithelial neoplasia II, cervical intraepithelial neoplasia III, and p16. To identify cases of difficult HGCIN with features intermediate between dysplasia and metaplasia, we reviewed all surgical cases of HGCIN that required p16 and Ki-67 diagnosis confirmation. Cases of interest were also stained with ProExC. Human papillomavirus screening and HPV 16/18 typing were performed by the Invader assays as described previously. Ten cases of classic HGCIN were easily diagnosed by hypercellularity, significant atypia, mitotic figures, and diffuse staining by p16, Ki67 and ProExC. The Invader assay identified HPV 16 (A9 positive/HPV16 positive) in 7 of 10 cases; the 3 others were A7 positive/not HPV18 (1) and A9 positive/not HPV16 (2). Eight cases of difficult HGCIN were identified. These showed only mild-to-moderate cellularity, a lack of significant atypia, absent-to-rare mitotic figures, and diffuse staining by p16, Ki-67, and ProExC. Human papillomavirus DNA was detected in 5 of 8 cases: only 1 was A9 positive/HPV16 positive, 1 was A5/A6 positive, 1 was A7 positive/not HPV18, and 2 were A9 positive/not HPV16. Three remaining cases demonstrated sufficient DNA to be analyzed by the Invader assay, but results were negative. This is a poorly recognized unusual group of cervical HGCIN with features intermediate between dysplasia and metaplasia that is easily confused by histologic examination. Immunostains prove the high-grade nature of these lesions, and Invader assay demonstrates association with HPV types other than 16/18 (ie, other HPV types detected by Invader assay). In this study, we present an unusual group of cases of high-grade dysplasia, not recognized by hematoxylin and eosin but identified by Ki67 and P16. It is very important to emphasize that this unusual group of high-grade dysplasias is associated with high-risk HPV but with types other than 16/18.

The 2 stromal compartments of the normal cervix with distinct immunophenotypic and histomorphologic features.

Cervical plasticity is partially attributed to subepithelial stromal cells. Knowing this population of cells in its variable physiologic states, with its immunophenotypic variations, will lead to better understanding of neoplastic processes related to these stromal cells. We reviewed slides of cervices from premenopausal, postmenopausal, and postpartum patients and used mesenchymal immunohistochemical stains. Results demonstrate 2 distinct subepithelial compartments, within the ectocervix and the endocervix/transformation zone. The endocervix/transformation zone has twice the number of stromal cells as the ectocervix, regardless of age. Ectocervical stromal cells are desmin+/smooth muscle actin (SMA)-, and endocervical stromal cells are desmin+/SMA-. In postpartum/premenopausal patients, the cervix has less desmin+ ectocervical and SMA- endocervical cells. In postmenopausal/prolapse patients, the cervix has no desmin+ ectocervical cells. Desmin+/SMA, calponin, caldesmon, myogenin, myoD1, CD34- cells could represent unusual myofibroblasts that should not be confused with a neoplastic process, especially if a mass is not present.

Detecting the "undetectable" alterations: Use of NGS to uncover high-risk alterations.

Copy number variants are common in patients with myeloid malignancies and may confer diagnostic, prognostic or therapeutic relevance. However, detection of these variants may require multiple testing modalities, which may not be available or ordered on all cases. We present a case that highlights the efficacy of copy number analysis by next generation sequencing to identify clinically relevant variants that may otherwise be missed by conventional cytogenetics and typical florescent in situ hybridization panels.

Diagnosing heparin-induced thrombocytopenia in mechanical circulatory support device patients.

BACKGROUND: Mechanical circulatory support device (MCSD) patients with positive heparin-induced thrombocytopenia (HIT) screening pose a unique challenge, as clinicians must make rapid decisions about their anticoagulation and whether they can safely undergo cardiopulmonary bypass. We identified screening practices at our institution and other institutions nationwide that differed from American Society of Hematology (ASH) guidelines. This discovery prompted a data review to confirm the applicability of guidelines to this unique population and to highlight complications of "gestalt" screening. METHODS: Our study included MCSD patients with HIT testing from April 2014 to August 2020. We evaluated 510 PF4 IgG ELISA results. RESULTS: HIT was confirmed in 4.2% of patients. There was an increased prevalence of HIT in patients with nondurable (5.3%) vs durable devices (2.9%) or those in the preimplantation setting (1.3%), however this difference was not statistically significant (p = 0.26). None of the patients with a low probability 4T Score had HIT. All patients with a high probability 4T Score and PF4 immunoassay OD >2.0 had HIT. False positive results occurred in 22% of assays ordered for patients with a low probability 4T Score. Twelve patients with a low probability 4T Score and a false positive immunoassay were switched to a direct thrombin inhibitor (DTI) while awaiting confirmatory results. Two patients experienced clinically significant bleeding after conversion to a DTI. An organ was refused in one patient with false positive HIT screening. CONCLUSIONS: Our findings demonstrate that an opportunity exists to improve clinical outcomes by re-emphasizing the utility of established guidelines and highlighting their safe use in the MCSD patient population.

Lack of PRAME Expression in Cutaneous T-Cell Lymphomas.

Cutaneous T-cell lymphomas (CTCLs) are rare tumors with no established markers that can reliably distinguish between benign and malignant lesions. Preferentially Expressed Antigen in Melanoma (PRAME) is a cancer/testis antigen that is found in many solid and hematologic malignancies. PRAME overexpression typically portends a poor prognosis and lower chemotherapeutic response. To date, no studies have established a role for PRAME in CTCL. An analysis was performed on 47 cases definitively diagnosed as CTCL: 25 cases of mycosis fungoides, 2 of Sezary syndrome, 5 of CD30+ lymphoproliferative disorder, 7 of primary cutaneous anaplastic large T-cell lymphoma, 3 of primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder, 1 of subcutaneous panniculitis-like T-cell lymphoma, and 4 of angiocentric T-cell lymphoma. PRAME immunohistochemistry was completely negative in all cases. PRAME expression was not found in any CTCL subtypes, suggesting that the pathogenesis of CTCL is not mediated by PRAME. Further study is required to identify biomarkers that might aid in the diagnosis and prognostication of CTCLs.

Consultative Interpretation for Lupus Anticoagulant by Expert Pathologist Reduces False-Positive Rates in the Era of Direct Oral Anticoagulants.

BACKGROUND: The diagnosis of antiphospholipid syndrome requires detection of antiphospholipid antibodies (aPL). A retrospective review of our testing practices revealed that societal recommendations for lupus anticoagulant (LA) testing as part of aPL testing are largely not followed by clinicians, and there was a high proportion of positive LA results. Increasing direct oral anticoagulant (DOAC) usage creates additional challenges in identifying LA. This prompted us to establish an order set with pathologist consultation ("LA panel") and testing algorithm to reduce false-positive LA and to ensure optimal LA identification and best practices for interpretation and follow-up. METHODS: The laboratory database was reviewed to determine the number of LA tests ordered and rate of LA positivity before and after the LA panel was instituted. We assessed the impact of pathologist consultation to minimize false-positive findings and on following diagnostic guidelines. RESULTS: LA panels were ordered for 1146 patients. LA was detected in 10% (111 of 1146) by dilute Russel viper venom time (dRVVT) normalized ratio [includes dRVVT screen (dRVVTs) positive/lupus-sensitive partial thromboplastin time (PTT-LA) positive and dRVVTs positive/PTT-LA negative] and 20% (228 of 1146) by Staclot-LA (includes dRVVTs negative/PTT-LA positive and dRVVTs positive/confirm negative). There was a reduction of false-positive LA by Staclot-LA; previously, 48% positive. We saw increased cancellation of LA testing for interfering anticoagulants [6.8% (16 of 236) vs 14.4% (55 of 383); P = 0.0061]. There was also increased adherence to follow-up LA testing [3% (8 of 236) vs 13.8% (53 of 383); P ≤ 0.001]. CONCLUSIONS: Creating a predetermined order set and testing algorithm with pathologist consultation improved LA testing interpretation and diagnostic follow-up testing.

Improved Recognition of Hematogones From Precursor B-Lymphoblastic Leukemia by a Single Tube Flow Cytometric Analysis.

OBJECTIVES: To improve diagnostic accuracy in differentiating hematogones from leukemic blasts in cases of precursor B-lymphoblastic leukemia/lymphoma (B-ALL), particularly those that are posttreatment or after bone marrow transplant, and to provide an algorithmic approach to this diagnostic challenge. METHODS: A seven-color antibody panel including CD10, CD19, CD45, CD38, CD34, CD58, and CD81 was generated to assess the feasibility of a single tube panel and provide an algorithmic approach to distinguish hematogones from B-ALL. Fifty-three cases were analyzed, and results were correlated with histology and ancillary studies. RESULTS: There was a significant difference in mean fluorescent intensity (MFI) for CD81 and CD58 when comparing hematogones and B-ALL populations (P < .001). B-ALL cases had a mean (SD) MFI of 24.6 (27.5; range, 2-125) for CD81 and 135.6 (72.6; range, 48-328) for CD58. Hematogones cases had a mean (SD) MFI of 70.2 (19.2; range, 42-123) for CD81 and 38.8 (9.4; range, 23-58) for CD58. CONCLUSIONS: The flow cytometry panel with the above markers and utilization of the proposed algorithmic approach provide differentiation of hematogones from B-ALL. This includes rare cases of hematogones and B-ALL overlap where additional ancillary studies are necessary.

Kaposi sarcoma-associated herpesvirus/human herpesvirus 8-associated extracavitary primary effusion lymphoma presenting as multiple lymphomatous polyposis.

Primary effusion lymphoma (PEL) is a distinct clinicopathological entity usually characterized by presentation as a lymphomatous body cavity effusion in the absence of solid tumor mass or dissemination during its clinical course. PEL can also rarely occur as a solid lymphoma involving nodal and extranodal sites and is referred to as extracavitary PEL. Here we report a unique case of extracavitary PEL in a 49-year-old HIV-seropositive patient who presented with vague abdominal pain and 20-lb weight loss. Esophagogastroduodenoscopy and colonoscopy revealed more than 100 broad-based intestinal polyps ranging from 2 mm to 3 cm in size, spreading from the duodenum to the rectum as a typical impression of "intestinal polyposis syndrome." Multiple biopsies demonstrated sheets of large lymphoid cells with characteristic features of extracavitary PEL with strong Kaposi sarcoma-associated herpesvirus/human herpesvirus 8 virus positivity by immunohistochemistry. Extracavitary PEL presenting as distinctive multiple lymphomatous polyposis as manifested in the case has not been described previously.

HHV8-negative effusion based lymphoma: a series of 17 cases at a single institution.

INTRODUCTION: Human herpesvirus 8-positive (HHV8+) primary effusion lymphoma is a well-recognized clinicopathologic entity. In contrast, HHV8-negative (HHV8-) effusion-based lymphoma (EBL) is incompletely characterized and under-recognized. We describe 17 cases of HHV8- EBL at our institution. MATERIALS AND METHODS: Cytology and available immunohistochemistry and cytogenetics were reviewed. Patient demographics, history, and outcome were obtained from medical records. RESULTS: The effusions were pleural (n = 9; 53%), peritoneal (n = 4; 24%), pericardial (n = 3; 18%), and pleural and pericardial (n = 1; 6%). Fifteen cases (88%) were CD20+ and 15 had sufficient information for classification by Hans algorithm (CD10, BCL6, MUM1): 11 (73%) nongerminal center and 4 (27%) germinal center phenotype. Epstein-Barr virus in situ hybridization was negative in 16 cases (94%). Three of 14 cases were MYC+ by immunohistochemistry. Fluorescence in situ hybridization, performed on 5 of the 17 cases, showed a MYC rearrangement in 1 case and a BCL6 rearrangement in 2 cases. Most patients were elderly (median age 86 years) and female (82%). Human immunodeficiency virus testing results, available in 4 patients, were negative. Seven (41%), including 1 of 2 heart transplant recipients, had congestive heart failure. Follow-up (5 days to 12 years) was available for 16 patients including 4 who survived ≥8 years. Only 1 of the 8 known deaths was clinically attributed to lymphoma. CONCLUSIONS: HHV8- lymphomas that occur in body cavity effusions without detectable lymphomatous masses are usually composed of large CD20+ lymphoid or lymphoplasmacytoid cells. In contrast to HHV8+ primary effusion lymphoma, patients with HHV8- EBL are usually elderly, lack a documented human immunodeficiency virus-positive history, and have a longer disease specific survival.

Expression of S100 Protein in CD4-positive T-cell Lymphomas Is Often Associated With T-cell Prolymphocytic Leukemia.

S100 T-cell lymphomas are infrequent, and except 1 all have been CD4 negative. On the basis of an index case of CD4 S100 T-cell prolymphocytic leukemia (T-PLL), we studied S100 protein expression in 19 additional T-PLLs and 56 other T-cell lymphomas that are usually CD4, including 15 angioimmunoblastic T-cell lymphomas, 24 anaplastic large cell lymphomas (16 ALK and 8 ALK), 7 mycosis fungoides/Sézary syndrome, and 10 peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS). Two additional S100 CD4 PTCL, NOS cases were also reviewed. Thirty percent (6/20) of T-PLLs were S100 compared with 0/56 other T-cell lymphomas with previously unstudied S100 reactivity (40 CD4, 2 CD8, 11 CD4/CD8, 3 unknown) (P=0.0007). There were no significant differences between the S100 and S100 T-PLLs with regard to the male:female ratio (2:1 vs. 1:1), age (71.6±7.7 vs. 65.4±9.3), peripheral blood lymphocyte count (67.2±116.6 vs. 101.1±159.7×10/L), or median survival (463 vs. 578 d, where known). The 2 S100 PTCL, NOS cases occurred in a 7-year-old boy and a 45-year-old woman. Both had involvement of the bone marrow and peripheral blood but were morphologically unlike T-PLL and lacked TCL1 gene rearrangement. These results demonstrate that S100 T-cell lymphomas include a subset that are CD4 and most often, but not exclusively, are T-PLL. Although having diagnostic implications, there were no documented clinical differences between the S100 and S100 T-PLLs.

Decreased Threshold of Aggregation to Low-Dose Epinephrine is Evidence of Platelet Hyperaggregability in Patients with Thrombosis.

Sticky platelet syndrome has been described as a hereditary thrombophilic condition. The aim of this study is to identify the presence of platelet hyperaggregability in patients who have experienced thrombosis. Light-transmittance platelet aggregometry was used to assess for spontaneous platelet aggregation, aggregation in response to full and low-dose (LD) epinephrine (Epi) and adenosine diphosphate, as well as arachidonic acid, and identify a distinct pattern of platelet hyperaggregability. Light-transmittance platelet aggregometry results were correlated with PFA-100® (Dade-Behring, Marburg, Germany) results, when available. An exaggerated response to LD Epi was found in 68% of patients with thrombosis compared to only 36% of healthy controls (P=0.034). Patients with thrombosis, either arterial or venous, demonstrated an exaggerated response to LD Epi nearly twice as frequently as healthy controls, even without significant family history of thrombophilia or other known risk factors for thrombosis. This suggests that platelet hyperaggregability may be multifactorial in nature and not necessarily hereditary.

Vascular pseudoinvasion in laparoscopic hysterectomy specimens for endometrial carcinoma: a grossing artifact?

Over several years, it has been a matter of debate whether or not the use of a uterine balloon manipulator during laparoscopic hysterectomies for endometrial carcinoma (EC) may cause tumor disruption resulting in a positive peritoneal cytology. More recently, this procedure has been associated with vascular pseudoinvasion in cases of low-risk EC. In this study, we evaluated a series of 21 cases of low-risk EC treated by laparoscopic hysterectomy (LH) to determine the incidence of this finding and to better characterize its histopathologic features. In addition, we reviewed 28 cases of low-risk EC treated by total abdominal hysterectomy (TAH) for comparison. Clinical information was obtained from patients' charts. Hematoxylin and eosin-stained slides were retrospectively reviewed in all cases. The following information was recorded: tumor grade and tumor stage according to the International Federation of Gynecology and Obstetrics, tumor shape (polypoid versus flat), presence or absence of vascular space involvement (VSI), size and location of the vessels with tumor involvement, concomitant presence of artifactual clefts in the myometrium with tumor involvement if applicable, presence or absence of lymph node sampling and the presence or absence of involvement at this site, and results of peritoneal cytology. Seven of 21 (33%) cases of low-risk EC treated by LH in this study showed VSI. None of the cases treated by TAH had VSI (P=0.001). In all of the cases of LH with VSI, the endometrial tumor was polypoid. VSI was detected only in large, thick-walled vessels in the outer myometrium or in ectatic vessels anywhere in the myometrium; no tumor fragments were seen in small vessels. The tumor in the VSI consisted of conspicuous fragments of tumors detached from the vascular wall. The VSI also lacked the inflammatory perivascular infiltrate seen in many cases of bona fide lymphovascular invasion. In addition, all of the cases with VSI also showed fragments of tumor in artifactual clefts in the myometrium. None of the cases of LH in which lymph node sampling and/or peritoneal cytology were obtained showed tumor at this site. In summary, our study confirms that LH is indeed associated with a higher rate of vascular pseudoinvasion when compared with TAH. However, we cannot attribute this phenomenon to mechanical disruption, displacement, and transport of tumor tissue into vascular spaces by the use of a uterine manipulator alone. Instead, we propose that pathologists may be generating postoperative pseudoinvasion by mechanically transporting tumor into vascular spaces during the grossing process. Proper recognition of this artifact is of utmost importance to avoid the overtreatment of patients undergoing LH for low-risk EC.