Benign fibro-osseous lesions (BFOLs) frequently display overlapping histological features. The differentiation of fibrous dysplasia (FD) from other BFOLs can be difficult, even for experienced orthopedic pathologists. Accurately distinguishing FD from other BFOLs may have significant clinical and treatment implications. A somatic mutation in gene GNAS encoding the ␣ subunit of the G protein (Gs␣) involving the codon corresponding to Arg 201 has been identified in FD and is specifically absent in other BFOLs. We have developed a quantitative assay by pyrosequencing that has a detection sensitivity of 95%. The test allows the identification of the two most common types of mutation (Arg¡His and Arg¡Cys) in a single reaction, with the ability to analyze other rare mutations. Of the 24 FD cases in this series, 23 (96%) were positive for GNAS/Gs␣ mutation. Nineteen of 23 positive cases exhibited a G¡A mutation (Arg¡His), whereas four had a C¡T mutation (Arg¡Cys). One of three BFOL, not otherwise specified cases was positive for G¡A mutation. None of the osteofibrous dysplasia, ossifying fibromas, or other bone lesions were positive for this mutation. Our experience is that pyrosequencing is an easy and accurate quantification method for Gs␣ mutation detection in fibrous dysplasia. Mutation analysis of the Gs␣ by pyrosequencing has significant potential for improving discrimination between FD and other BFOLs in problematic cases. Fibrous dysplasia is a benign fibro-osseous lesion (BFOL) of the medullary cavity, which may involve one or more bones.1 Because fibrous dysplasia (FD) and other BFOLs frequently display overlapping histological features, differentiation of FD from a BFOL can be difficult, even for experienced orthopedic pathologists, particularly on small biopsy samples.2,3 A somatic mutation at codon 201 of the ␣ subunit of G protein (Gs␣), encoded by the GNAS gene, has been identified in FD (monostotic and polyostotic forms) and in multiple endocrinopathies of McCune-Albright syndrome, 4 but is specifically absent in other BFOLs, such as osteofibrous dysplasia.3,5,6 Point mutations result in replacement of Arg (CGT) at position 201 with, most commonly, His (CAT) or Cys (TGT) 4 ; and in rare cases, with Ser (AGT), 7 Leu (CTT), 8 or Gly (GGT). 9The mutated Gs␣ is constitutively activated, leading to cAMP activation and downstream physiological responses in affected tissues, including bone, skin, endocrine glands, and other tissues. 4,10,11 Because of the mosaic nature of this mutation, the distribution of mutant cells and the ratio of mutant to normal cells in a lesion or affected individual may be reflected in the severity of phenotypic expression.10,11 Interestingly, the percentage of mutant stem cells decreases as a lesion ages resulting in "normalization" of FD of bone.12 Addressing these issues require an extremely sensitive and accurate quantitative assay for Arg201 mutation detection.Many detection assays have been developed to identify the Arg201 mutations. The two most widely used methods are direct ...

Gastric extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MZL-MALT) is speculated to be immune mediated and is notable for responding to treatment by Helicobacter pylori eradication. However, the gastric MZL-MALT with t(11;18)(q21;q21) has been shown to be resistant to treatment by H. pylori eradication. We studied the molecular, immunohistochemical, and histological aspects of 48 cases of gastric MZL-MALT and used a reverse transcription real-time PCR assay to assess the presence of a t(11;18)(q21;q21) in formalin-fixed, paraffin-embedded tissue. Florescence in situ hybridization for t(11:18)(q21;q21) was used to confirm the real-time PCR results. Three distinct morphological subtypes were recognized: monocytoid, small lymphocytic, and plasmacytoid. Morphology, immunophenotype, and immunoglobulin heavy chain (IgH) gene rearrangement were correlated with the results of the t(11:18)(q21;q21) assay. Of the 48 analyzed cases, 15 (31%) were positive for t(11;18)(q21;q21) and 33 (69%) were monoclonal for IgH gene rearrangement. Of the 15, 13 (87%) cases with t(11;18)(q21;q21) translocation showed IgH gene rearrangement by PCR. Of the 33 t(11;18)(q21;q21)-negative cases tested, 20 cases (61%) showed IgH gene rearrangement. The 15 t(11;18)(q21;q21) translocation-positive cases had either monocytoid (12 of 15) or small lymphocytic morphology (3 of 15). Aberrant expression of CD43 was observed in 8 of 15 (53%) t(11;18)(q21;q21)-positive cases and 21 of 31 (68%) t(11;18)(q21;q21)-negative cases. Our data show that t(11;18)(q21;q21)-positive MZL-MALTs frequently show monocytoid morphology, less often small lymphocytic morphology, and not purely plasmacytoid morphology. Identification of a t(11;18)(q21;q21) by reverse transcription real-time PCR is highly specific for MZL-MALT and helps in the diagnosis of MZL-MALT. Studying the correlation between this translocation and morphological features may increase our understanding of the role of this translocation in the pathogenesis and the clinical behavior of gastric MZL-MALT.

We demonstrate that high-frequency and high-intensity ultrasound (US) can be applied to both tissue fixation and tissue processing to complete the conventional overnight formalin-fixation and paraffin-embedding (FFPE) procedures within 1 hr. US-facilitated FFPE retains superior tissue morphology and long-term room temperature storage stability than conventional FFPE. There is less alteration of protein antigenicity after US-FFPE preservation so that rapid immunohistochemical reactions occur with higher sensitivity and intensity, reducing the need for antigen retrieval pretreatment. US-FFPE tissues present storage stability so that room temperature storage up to 7 years does not significantly affect tissue morphology, protein antigenic properties, RNA distribution, localization, and quantitation. In addition, during fixation, tissue displays physical changes that can be monitored and reflected as changes in transmission US signals. As far as we know, this is the first effort to monitor tissue physical changes during fixation. Further study of this phenomenon may provide a method to control and to monitor the level of fixation for quality controls. The mechanism of less alteration of protein antigenicity by US-FFPE was discussed.

We describe what are, to our knowledge, the first reported primary colonic MALT lymphoma carrying t(14;18)(q32;q21)/IGH-MALT1, and one of the few reported cases of gastric MALT lymphoma with this translocation. As this translocation is seen in only a few gastrointestinal MALT lymphomas, it is not useful as a diagnostic marker for routine clinical services. Although these findings suggest that t(14;18)/IGH-MALT1 is a rare molecular event in gastrointestinal MALT lymphomas and DLBCLs, further studies to elucidate the role of this genetic alteration in these diseases are indicated.

Background This study aimed to facilitate the understanding of the transmission route and risk factors that might contribute to the infection of Kaposi’s sarcoma associated herpesvirus (KSHV) among men who have sex with men (MSM). Methods A cross-sectional study of 520 subjects was conducted in Shanghai, China in 2020. Plasma samples were collected and screened for KSHV, HIV, HBV, HCV, and syphilis. Univariate and multivariate logistic regression analyses were conducted to explore potential correlates of KSHV infection. Results The overall seroprevalence of KSHV was 43.8%, with an adjusted value of 29.8% according to the sensitivity and specificity of the KSHV screening assay. Individuals with lower levels of monthly income (Chi-sqauretrend = 4.11, P = 0.043) and more male sex partners (Chi-sqauretrend = 6.06, P = 0.014) were more likely to be infected with KSHV. Also, KSHV seropositivity was positively associated with being a student (aOR = 1.96; 95%CI: 1.09–3.61), being coinfected with HCV (aOR = 2.61; 95%CI: 1.05–7.10), and syphilis (aOR = 2.91; 95%CI: 1.30–6.89). Conclusions The prevalence of KSHV in MSM remains high. As a risky sexual behavior, having multiple male sex partners is a key contributor to KSHV infection among this population. Efforts designed to control modifiable risk factors in order to reduce the burden of KSHV infection are indispensable. High KSHV seroprevalence among students MSM deserves more attention.