Impact of melphalan day -1 vs day -2 on outcomes after autologous stem cell transplant for multiple myeloma.

Background: Melphalan is the most common conditioning regimen used prior to autologous stem cell transplant (ASCT); however, there are varying data on optimal melphalan timing prior to transplant for best safety and efficacy. Historically, ASCT conditioning consisted of melphalan 200 mg/m2 on day 2 (D-2) (48 h prior to ASCT), but many institutions have since adopted a melphalan protocol with administration on day 1 (D-1) (24 h prior to SCT) or split dosing over the 2 days. The optimal timing of melphalan has yet to be determined. Methods: In this single-center retrospective study, we analyzed transplant outcomes for patients between March 2011 and September 2020 admitted for high-dose, single-agent melphalan 200 mg/m2 on D-1 vs. D-2. The primary outcomes were time to neutrophil and platelet engraftment. Secondary outcomes include incidence of hospital readmission within 30 days, 2-year progression-free survival, and 2-year overall survival. Results: A total of 366 patients were studied (D-2 n = 269 and D-1 n = 97). The incidence of high-risk cytogenetics was similar between the two groups (37% vs. 40%). Median days to absolute neutrophil count engraftment was similar at 11 days in the D-2 and D-1 cohort (n = 269, range 0-14, IQR 11-11 vs. n = 97, range 0-14, IQR 11-12). Median days to platelet engraftment >20,000/mcL was 18 days for D-2 melphalan (range: 0-28, IQR 17-20) versus 19 days for D-1 melphalan (range: 0-32, IQR 17-21). Overall survival at 2 years post-transplant was similar in both cohorts (94%; p = 0.76), and PFS was 70% in D-2 compared with 78% in D-1 (p = 0.15). In a multivariable model including age and performance status, hospital readmission within 30 days of transplant was higher in the D-1 cohort (odds ratio 1.9; p = 0.01). Conclusion: This study demonstrates similar neutrophil and platelet engraftment in D-1 and D-2 melphalan cohorts with similar 2-year PFS and OS. Either D-2 or D-1 melphalan dosing schedule is safe and effective.

Current Laboratory Testing Practices for Assessment of ERBB2/HER2 in Endometrial Serous Carcinoma and Colorectal Carcinoma.

CONTEXT.­: Therapy targeted at human epidermal growth factor receptor 2 (HER2; also known as ERBB2) was used initially for breast and gastroesophageal carcinoma and has more recently been adopted for endometrial serous carcinoma (ESC) and colorectal carcinoma (CRC). There is evidence that predictive biomarker testing algorithms for HER2 must be tumor type specific and that an algorithm validated for one tumor type cannot be applied to another. OBJECTIVE.­: To describe current laboratory practices for HER2 assessment in ESC and CRC. DESIGN.­: We surveyed laboratories participating in the 2021 College of American Pathologists (CAP) HER2 immunohistochemistry proficiency testing program. RESULTS.­: The survey was distributed to 1548 laboratories and returned by 1195, of which 83.5% (998) were in the United States. For ESC, 24.0% (287) of laboratories reported performing in-house testing for HER2 by immunohistochemical staining and/or in situ hybridization; of these, 44.3% (127) performed it reflexively on all cases of ESC. The most common criterion for evaluating HER2 was the American Society of Clinical Oncology/CAP 2018 guideline for breast carcinoma (69.0%; 194 of 281), whereas only 16.0% (45) of laboratories used guidelines specific to ESC. For CRC, 20.2% (239 of 1185) of laboratories performed in-house HER2 testing, and 82.0% of these (196) did the test only at the clinician's request. A plurality (49.4%; 115 of 233) used gastroesophageal cancer guidelines when scoring CRC, 30.0% (70) used the CRC scoring system from the HERACLES trial, and 16.3% (38) used the American Society of Clinical Oncology/CAP 2018 guideline for breast carcinoma. CONCLUSIONS.­: Laboratories vary in their approach to HER2 testing in ESC and CRC. Most laboratories did not report using tumor type-specific recommendations for HER2 interpretation. The lack of standardization could present a challenge to evidence-based practice when considering targeted therapy for these diseases.

Congenital Infantile Fibrosarcoma Involving Pelvic Wall and Thigh Soft Tissues and Placenta, Presenting with Coagulopathy.

Infantile fibrosarcoma (IF) is a well characterized pediatric malignancy marked by gene rearrangements involving members of the NTRK family. In this report, we present a case of IF that presented in the inguinal region-proximal thigh and was initially thought to be a kaposiform hemangioendothelioma (KHE) because it presented with a bleeding diathesis thought to be Kasabach-Merritt phenomenon (KMP). Subsequently, the placental examination showed a neoplasm in the perivascular-subendothelial space of stem villi, initially thought to be myofibromatosis. Ultimately, a biopsy of the thigh mass showed IF with an NTRK3-ETV6 fusion. Subsequent FISH analysis of the placenta showed an ETV6 rearrangement confirming that it was also IF. Review of the laboratory studies suggests that disseminated intravascular coagulation may have been more likely than KMP, highlighting the difficulty in making this distinction in some cases. We believe this to be the first report of an IF presenting in a soft tissue site and the placenta, and discuss the possible mechanisms that could have allowed the IF in the leg to spread to the placenta.

Secondary cytogenetic abnormalities in core-binding factor AML harboring inv(16) vs t(8;21).

Patients with core-binding factor (CBF) acute myeloid leukemia (AML), caused by either t(8;21)(q22;q22) or inv(16)(p13q22)/t(16;16)(p13;q22), have higher complete remission rates and longer survival than patients with other subtypes of AML. However, ∼40% of patients relapse, and the literature suggests that patients with inv(16) fare differently from those with t(8;21). We retrospectively analyzed 537 patients with CBF-AML, focusing on additional cytogenetic aberrations to examine their impact on clinical outcomes. Trisomies of chromosomes 8, 21, or 22 were significantly more common in patients with inv(16)/t(16;16): 16% vs 7%, 6% vs 0%, and 17% vs 0%, respectively. In contrast, del(9q) and loss of a sex chromosome were more frequent in patients with t(8;21): 15% vs 0.4% for del(9q), 37% vs 0% for loss of X in females, and 44% vs 5% for loss of Y in males. Hyperdiploidy was more frequent in patients with inv(16) (25% vs 9%, whereas hypodiploidy was more frequent in patients with t(8;21) (37% vs 3%. In multivariable analyses (adjusted for age, white blood counts at diagnosis, and KIT mutation status), trisomy 8 was associated with improved overall survival (OS) in inv(16), whereas the presence of other chromosomal abnormalities (not trisomy 8) was associated with decreased OS. In patients with t(8;21), hypodiploidy was associated with improved disease-free survival; hyperdiploidy and del(9q) were associated with improved OS. KIT mutation (either positive or not tested, compared with negative) conferred poor prognoses in univariate analysis only in patients with t(8;21).

Conventional Cytogenetic Analysis of Hematologic Neoplasms: A 20-Year Review of Proficiency Test Results From the College of American Pathologists/American College of Medical Genetics and Genomics Cytogenetics Committee.

CONTEXT.­: One goal of the joint College of American Pathologists/American College of Medical Genetics and Genomics Cytogenetics Committee is to ensure the accurate detection and description of chromosomal abnormalities in both constitutional and neoplastic specimens, including hematologic neoplasms. OBJECTIVE.­: To report a 20-year performance summary (1999-2018) of conventional chromosome challenges focusing on hematologic neoplasms. DESIGN.­: A retrospective review was performed from 1999 through 2018 to identify karyotype challenges specifically addressing hematologic neoplasms. The overall performance of participants was examined to identify potential recurring errors of clinical significance. RESULTS.­: Of 288 total conventional chromosome challenges from 1999-2018, 87 (30.2%) were presented in the context of a hematologic neoplasm, based on the provided clinical history, specimen type, and/or chromosomal abnormalities. For these 87 hematologic neoplasm challenges, 91 individual cases were provided and graded on the basis of abnormality recognition and karyotype nomenclature (ISCN, International System for Human Cytogenomic [previously Cytogenetic] Nomenclature). Of the 91 cases, 89 (97.8%) and 87 (95.6%) exceeded the required 80% consensus for grading of abnormality recognition and correct karyotype nomenclature, respectively. The 2 cases (2 of 91; 2.2%) that failed to meet the 80% consensus for abnormality recognition had complex karyotypes. The 4 cases (4 of 91; 4.4%) that failed to meet the 80% consensus for correct karyotype nomenclature were the result of incorrect abnormality recognition (2 cases), missing brackets in the karyotype (1 case), and incorrect breakpoint designation (1 case). CONCLUSIONS.­: This 20-year review demonstrates clinical cytogenetics laboratories have been and continue to be highly proficient in the detection and description of chromosomal abnormalities associated with hematologic neoplasms.

Human epidermal growth factor 2 (HER2) in early stage uterine serous carcinoma: A multi-institutional cohort study.

BACKGROUND: Human epidermal growth factor receptor 2 (HER2) has emerged as an important prognostic and therapeutic target in advanced stage and recurrent uterine serous carcinoma (USC). The significance of tumoral HER2 expression in early-stage disease has not been established. METHODS: This multi-center cohort study included women with stage I USC treated from 2000 to 2019. Demographic, treatment, recurrence, and survival data were collected. Immunohistochemistry (IHC) was performed for HER2 and scored 0-3+. Equivocal IHC results (2+) were further tested with fluorescence in-situ hybridization (FISH). HER2 positivity was defined as 3+ IHC or FISH positive. RESULTS: One hundred sixty-nine patients with stage I USC were tested for HER2; 26% were HER2-positive. There were no significant differences in age, race, stage, adjuvant therapy, or follow-up duration between the HER2-positive and negative cohorts. Presence of lymph-vascular space invasion was correlated with HER2-positive tumors (p = .003). After a median follow-up of 50 months, there were 43 (25.4%) recurrences. There were significantly more recurrences in the HER2-positive cohort (50.0% vs 16.8%, p < .001). HER2 positive tumors were associated with worse progression-free (PFS) and overall survival (OS) (p < .001 and p = .024). On multivariate analysis, HER2 positive tumors were associated with inferior PFS (aHR 3.50, 95%CI 1.84-6.67; p < .001) and OS (aHR 2.00, 95%CI 1.04-3.88; p = .039) compared to HER2-negative tumors. CONCLUSIONS: Given its significant association with worse recurrence and survival outcomes, HER2 positivity appears to be a prognostic biomarker in women with stage I uterine serous carcinoma. These data provide support for clinical trials with anti-HER2-directed therapy in early-stage disease.

Impact of cytogenetic abnormalities on outcomes of adult Philadelphia-negative acute lymphoblastic leukemia after allogeneic hematopoietic stem cell transplantation: a study by the Acute Leukemia Working Committee of the Center for International Blood and Marrow Transplant Research.

Cytogenetic risk stratification at diagnosis has long been one of the most useful tools to assess prognosis in acute lymphoblastic leukemia (ALL). To examine the prognostic impact of cytogenetic abnormalities on outcomes after allogeneic hematopoietic cell transplantation, we studied 1731 adults with Philadelphia-negative ALL in complete remission who underwent myeloablative or reduced intensity/non-myeloablative conditioning transplant from unrelated or matched sibling donors reported to the Center for International Blood and Marrow Transplant Research. A total of 632 patients had abnormal conventional metaphase cytogenetics. The leukemia-free survival and overall survival rates at 5 years after transplantation in patients with abnormal cytogenetics were 40% and 42%, respectively, which were similar to those in patients with a normal karyotype. Of the previously established cytogenetic risk classifications, modified Medical Research Council-Eastern Cooperative Oncology Group score was the only independent prognosticator of leukemia-free survival (P=0.03). In the multivariable analysis, monosomy 7 predicted post-transplant relapse [hazard ratio (HR)=2.11; 95% confidence interval (95% CI): 1.04-4.27] and treatment failure (HR=1.97; 95% CI: 1.20-3.24). Complex karyotype was prognostic for relapse (HR=1.69; 95% CI: 1.06-2.69), whereas t(8;14) predicted treatment failure (HR=2.85; 95% CI: 1.35-6.02) and overall mortality (HR=3.03; 95% CI: 1.44-6.41). This large study suggested a novel transplant-specific cytogenetic scheme with adverse [monosomy 7, complex karyotype, del(7q), t(8;14), t(11;19), del(11q), tetraploidy/near triploidy], intermediate (normal karyotype and all other abnormalities), and favorable (high hyperdiploidy) risks to prognosticate leukemia-free survival (P=0.02). Although some previously established high-risk Philadelphia-negative cytogenetic abnormalities in ALL can be overcome by transplantation, monosomy 7, complex karyotype, and t(8;14) continue to pose significant risks and yield inferior outcomes.

Plasmacytoid cells in salivary pleomorphic adenoma: an alternative interpretation of their immunohistochemical characteristics highlights function and capability for epithelial-mesenchymal transition.

OBJECTIVES: Plasmacytoid cells (PLCs) in salivary pleomorphic adenoma (SPA) are regarded as modified neoplastic myoepithelia and define plasmacytoid myoepithelioma (pMYO). However, histochemically, immunohistochemically and ultrastructurally, PLCs fail to demonstrate frank myogenous properties. Epithelial-mesenchymal transition (EMT) may explain the phenotypes in SPA. Our aim was to evaluate (1) PLCs with accepted or purported myoepithelial and EMT-related markers; and (2) pMYOs for PLAG1 aberrations by using fluorescence in situ hybridization. STUDY DESIGN: Eight SPAs with or without PLC-predominance and 3 pMYOs were immunohistochemically studied. RESULTS: PLCs in SPA and pMYO exhibited strong, scattered to diffuse positivity for K7, rare K14 positivity and were mostly negative for α-smooth muscle actin, h-caldesmon, and p63/p40. S100 staining was strong and diffuse, whereas calponin was variable. DOG1 was negative. PLCs in pMYO and PLC-rich SPA exhibited selective or diffuse WT1 and D2-40 immunoreactivity. EMT markers SNAIL/SLUG exhibited strong and variable immunoreactivity in PLCs in contrast to weak or absent E-cadherin expression. SOX10 was diffusely and strongly positive. PLAG1 rearrangement was present in 1 pMYO. CONCLUSIONS: PLCs mostly fail to express myoepithelial markers; PLCs are neoplastic cells adapting to microenvironmental changes and capable of EMT; and tumors composed solely of PLCs are apparently SPAs depleted of a ductal component.

CD161 Is Expressed in a Subset of T-Cell Prolymphocytic Leukemia Cases and Is Useful for Disease Follow-up.

OBJECTIVES: CD161 (NKRP1) is a lectin-like receptor present on NK cells and rare T-cell subsets. We have observed CD161 expression in some cases of T-cell prolymphocytic leukemia (T-PLL) and found it to be useful in follow-up and detection of disease after treatment. METHODS: Retrospective review of T-PLL cases with complete flow cytometry data including CD161. RESULTS: We identified 10 cases of T-PLL with flow cytometric evaluation of CD161 available. Six of these cases were positive for CD161 expression. All CD161-positive cases were positive for CD8 with variable CD4 expression, whereas all CD161-negative cases were negative for CD8. In a case with two neoplastic subsets positive and negative for CD8, only the former expressed CD161. CONCLUSIONS: These novel results suggest that CD161 is often aberrantly expressed in a defined subset of T-PLL positive for CD8. We are showing the utility of this immunophenotype in diagnosis and follow-up.

Core-binding factor acute myeloid leukemia with t(8;21): Risk factors and a novel scoring system (I-CBFit).

BACKGROUND: Although the prognosis of core-binding factor (CBF) acute myeloid leukemia (AML) is better than other subtypes of AML, 30% of patients still relapse and may require allogeneic hematopoietic cell transplantation (alloHCT). However, there is no validated widely accepted scoring system to predict patient subsets with higher risk of relapse. METHODS: Eleven centers in the US and Europe evaluated 247 patients with t(8;21)(q22;q22). RESULTS: Complete remission (CR) rate was high (92.7%), yet relapse occurred in 27.1% of patients. A total of 24.7% of patients received alloHCT. The median disease-free (DFS) and overall (OS) survival were 20.8 and 31.2 months, respectively. Age, KIT D816V mutated (11.3%) or nontested (36.4%) compared with KIT D816V wild type (52.5%), high white blood cell counts (WBC), and pseudodiploidy compared with hyper- or hypodiploidy were included in a scoring system (named I-CBFit). DFS rate at 2 years was 76% for patients with a low-risk I-CBFit score compared with 36% for those with a high-risk I-CBFit score (P < 0.0001). Low- vs high-risk OS at 2 years was 89% vs 51% (P < 0.0001). CONCLUSIONS: I-CBFit composed of readily available risk factors can be useful to tailor the therapy of patients, especially for whom alloHCT is not need in CR1 (ie, patients with a low-risk I-CBFit score).

Comparative Performance of Breast Cancer Human Epidermal Growth Factor Receptor 2 Fluorescence In Situ Hybridization and Brightfield In Situ Hybridization on College of American Pathologists Proficiency Tests.

CONTEXT.­: Fluorescence in situ hybridization (FISH) and brightfield in situ hybridization (ISH) are 2 clinically approved laboratory methods for detecting ERBB2 (HER2) amplification in breast cancer. OBJECTIVE.­: To compare the performance of FISH and brightfield ISH on proficiency testing administered by the College of American Pathologists Laboratory Accreditation Program. DESIGN.­: Retrospective review was performed on 70 tissue core samples in 7 separate proficiency testing surveys conducted between 2009 and 2013. RESULTS.­: The samples included 13 consensus-amplified tissue cores, 53 consensus-nonamplified cores, and 4 cores that did not reach consensus for FISH and/or brightfield ISH. There were 2552 individual responses for FISH and 1871 individual responses for brightfield ISH. Consensus response rates were comparable for FISH (2474 of 2524; 98.0%) and brightfield ISH (2135 of 2189; 97.5%). The FISH analysis yielded an average HER2 copy number per cell that was significantly higher (by 2.86; P = .02) compared with brightfield ISH for amplified cores. For nonamplified cores, FISH yielded slightly, but not significantly, higher (by 0.17; P = .10) HER2 copy numbers per cell. There was no significant difference in the average HER2 to control ratio for either consensus-amplified or consensus-nonamplified cores. Participants reported "unable to analyze" more frequently for brightfield ISH (244 of 2453; 9.9%) than they did for FISH (160 of 2684; 6.0%). CONCLUSIONS.­: Our study indicates a high concordance rate in proficiency testing surveys, with some significant differences noted in the technical performance of these assays. In borderline cases, updated American Society of Clinical Oncology/College of American Pathologists cutoff thresholds that place greater emphasis on HER2 copy number per cell could accentuate those differences between FISH and brightfield ISH.

Plasma Cell Myeloma in Children and Young Adults: A Report of 4 Cases From a Single Institution and a Review of the Literature.

Plasma cell myeloma (PCM) is rare in children and young adults and therefore may be difficult to diagnose. Here we report the clinicopathologic findings of 4 patients under the age of 30 diagnosed with PCM at our institution and summarize the literature about 48 other cases of PCM in this age group. The male:female ratio was 1.2:1 and the number of cases increased with age. Children and young adults with PCM often present with a plasmacytoma and are less likely to have asymptomatic PCM than their adult counterparts. From the cases that reported ethnicity, the majority (55%) were non-white suggesting a possible ethnic predisposition to PCM in this age group. PCM should be included in the differential diagnosis of mass lesions, especially a destructive bony lesion, after more common causes have been ruled out in this age group. The optimal treatment for PCM in this patient population is unclear and conclusions into this are hampered by the paucity of cases and the lack of standardized follow-up.

Hyalinizing Clear Cell Carcinoma of the Bronchus.

Hyalinizing clear cell carcinoma (HCCC) is an uncommon low-grade minor salivary gland neoplasm that usually arises in the head and neck region. We report a 55-year-old man who presented with a 2.5 cm lung mass that was partially obstructing the right bronchus intermedius. The tumor consisted of cords and nests of clear and eosinophilic cells in a hyalinized stromal background. The neoplastic cells expressed cytokeratin (CK) 7, CK 5/6, high-molecular weight cytokeratin (34BE12), p63 and p40, while TTF-1, napsin A, CK20, S100, smooth muscle actin, synaptophysin and chromogranin were negative. Mucicarmine stain also was negative in the lesional cells. Fluorescence in situ hybridization using break apart probes revealed rearrangement of the Ewing Sarcoma Breakpoint Region 1 gene locus. The morphologic, immunophenotypic and cytogenetic findings confirmed the diagnosis of HCCC, most likely of bronchial submucosal gland origin. To our knowledge, only two other reports of primary pulmonary HCCC are available in English literature.

Ewing Sarcoma and Atypical Teratoid Rhabdoid Tumor: A FISH and Immunohistochemical Comparison.

Ewing sarcoma (ES) and atypical teratoid rhabdoid tumor (ATRT) are high-grade malignancies of childhood, each of which is associated with genetic abnormalities on chromosome 22. ES is typically characterized by rearrangement of the EWSR1 locus and ATRT by deletion of SMARCB1. We report a case with an unusual fluorescence in situ hybridization signal pattern consistent with EWSR1 rearrangement that was shown to have loss of INI1 expression by immunohistochemistry due to deletion in the long arm of one chromosome 22. In light of the unusual findings in this case as well as the proximity of the EWSR1 locus and SMARCB1 locus on chromosome 22 and frequent CD99 staining in both tumors, we examined 16 ES cases and 17 ATRT, renal rhabdoid tumor (RRT), and extrarenal rhabdoid tumor (ERRT) cases for CD99 and INI1 staining and for EWSR1 rearrangement. Staining with INI1 was negative in ATRT, RRT, and ERRT and positive in ES cases; CD99 was positive in ES cases and variable in ATRT cases. All but 2 cases of ES, and no cases of ATRT, showed rearrangement of EWSR1. The present case appears to be best classified as a unique variant of ATRT based on immunohistochemistry, EWSR1 fluorescence in situ hybridization and RT-PCR, and SMARCB1 gene sequencing.