Geographic Variability of Nodular Lymphocyte-Predominant Hodgkin Lymphoma.

OBJECTIVES: Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) differs from classic Hodgkin lymphoma (CHL) in terms of clinicopathologic features, including Epstein-Barr virus (EBV) association. CHL geographic variability is well known, with higher frequencies of mixed-cellularity subtype and EBV positivity in low/middle-income countries (LMICs), but there are few well-characterized series of NLPHL from LMICs. METHODS: We detail clinicopathologic findings of 21 NLPHL cases received in consultation from Kenya and summarize reports of NLPHL with EBV testing published since 2000. RESULTS: Median age of consultation cases was 36 years, and male/female ratio was 3.2. All cases involved peripheral lymph nodes and showed at least some B-cell-rich nodular immunoarchitecture, with prominent extranodular lymphocyte-predominant (LP) cells and T-cell-rich variant patterns most commonly seen. LP cells expressed pan-B-cell markers, including strong OCT2; lacked CD30 and CD15 expression in most cases; and were in a background of expanded/disrupted follicular dendritic cell meshworks and increased T-follicular helper cells. LP cells were EBV negative in 18 cases. Historical cases showed a low rate of EBV positivity with no significant difference between LMICs and high-income countries. CONCLUSIONS: Unlike CHL, NLPHL shows few geographic differences in terms of clinicopathologic features and EBV association. These findings have implications for diagnosis, prognostication, and treatment of patients with NLPHL in LMICs.

Xpert® MTB/RIF assay on formalin-fixed paraffin-embedded tissues in the diagnosis of extrapulmonary tuberculosis.

BACKGROUND: Diagnosis of extrapulmonary tuberculosis continues to be a challenge due to the complexity of the causative organism and the wide array of pathologic features seen in this infection. Xpert MTB/RIF can be used on fresh or frozen tissue specimens for diagnosis of tuberculosis with good results. However, there is little data on its use with formalin-fixed paraffin-embedded (FFPE) tissues. OBJECTIVES: The aim of this study was to demonstrate the potential utility of Xpert MTB/RIF and to compare its performance to Ziehl-Neelsen staining for the detection of Mycobacterium tuberculosis from FFPE tissues using histological features from haematoxylin and eosin staining as the gold standard. METHODS: Eighty randomly selected archival FFPE tissues exhibiting histological features of tuberculosis were included in the study. After deparaffinisation and lysis, all the tissue specimens were subjected to the Xpert® MTB/RIF assay. The outcome measures were proportions of positively identified cases by each test. RESULTS: Using histology as the gold standard, the sensitivity of Ziehl-Neelsen staining was 20.3% (95% confidence interval: 12% - 30.8%), and the sensitivity of the Xpert® MTB/RIF assay was 53.2% (95% confidence interval: 41.6% - 64.9%); the difference was statistically significant (p = 0.002). None of the cases tested positive for rifampicin resistance. CONCLUSION: With prior deparaffinisation and lysis, FFPE tissues are amenable to testing by Xpert® MTB/RIF assay. A validation study to determine the clinical utility, analytical optimisation and cost implications of this assay for FFPE tissues is recommended.

Sentinel Lymph Node Biopsy Pathology and 2-Year Postsurgical Recurrence of Breast Cancer in Kenyan Women.

PURPOSE: The goal of this study was to describe the pathologic findings and early follow-up experience of patients who underwent a sentinel lymph node biopsy (SLNB) at Aga Khan University Hospital (AKUH) between 2008 and 2017. PATIENTS AND METHODS: We performed a retrospective analysis of women with breast cancer who underwent an SLNB at AKUH between 2008 and 2017. The SLNB was performed on patients with stage I and stage II breast cancer, and identification of the sentinel lymph node was made by radioactive tracer, blue dye, or both, per availability and surgeon preference. Demographic, surgical, and pathologic data, including immunohistochemistry of the surgical sample for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2, were abstracted from the patient records. Follow-up data were available for a subset of patients. RESULTS: Between 2008 and 2017, six surgeons performed SLNBs on 138 women, 129 of whom had complete records and were included in the study. Thirty-one of 129 (24%) had a positive SLNB, including 10 of 73 (14%) with stage I and 21 of 56 (38%) with stage II disease. Seventy-eight patients (60%) received systemic adjuvant chemotherapy and 79 (62%) received radiation therapy, and of the 102 patients who were estrogen receptor positive, 86 (85%) received endocrine therapy. Seventy-nine patients were observed for > 2 years, and, of these, four (5.1%) had a regional recurrence. CONCLUSION: The SLNB positivity rates were similar to those of high-income country (HIC) cohorts. However, preliminary data suggest that recurrence rates are elevated at AKUH as compared with those of HIC cohorts, perhaps because of a lower use of radiotherapy and chemotherapy at AKUH compared with HIC cohorts or because of differences in the characteristics of the primary tumor in patients at AKUH as compared with those in HICs.