Bromocriptine sensitivity in bromocriptine-induced drug-resistant prolactinomas is restored by inhibiting FGF19/FGFR4/PRL.

PURPOSE: At present, various treatment strategies are available for pituitary adenomas, including medications, surgery and radiation. The guidelines indicate that pharmacological treatments, such as bromocriptine (BRC) and cabergoline (CAB), are important treatments for prolactinomas, but drug resistance is an urgent problem that needs to be addressed. Therefore, exploring the mechanism of drug resistance in prolactinomas is beneficial for clinical treatment. METHODS: In our research, BRC-induced drug-resistant cells were established. Previous RNA sequencing data and an online database were used for preliminary screening of resistance-related genes. Cell survival was determined by Cell Counting Kit-8 (CCK-8) assay, colony formation assays and flow cytometry. Quantitative real-time polymerase chain reaction (qRT‒PCR), western blotting, immunohistochemistry, immunofluorescence and Co-immunoprecipitation (Co-IP) were used to assess the molecular changes and regulation. The therapeutic efficacy of BRC and FGFR4 inhibitor fisogatinib (FISO) combination was evaluated in drug-resistant cells and xenograft tumors in nude mice. RESULTS: Consistent with the preliminary results of RNA sequencing and database screening, fibroblast growth factor 19 (FGF19) expression was elevated in drug-resistant cells and tumor samples. With FGF19 silencing, drug-resistant cells exhibited increased sensitivity to BRC and decreased intracellular phosphorylated fibroblast growth factor receptor 4 (FGFR4) levels. After confirming that FGF19 binds to FGFR4 in prolactinoma cells, we found that FGF19/FGFR4 regulated prolactin (PRL) synthesis through the ERK1/2 and JNK signaling pathways. Regarding the effect of targeting FGF19/FGFR4 on BRC efficacy, FISO and BRC synergistically inhibited the growth of tumor cells, promoted apoptosis and reduced PRL levels. CONCLUSION: Overall, our study revealed FGF19/FGFR4 as a new mechanism involved in the drug resistance of prolactinomas, and combination therapy targeting the pathway could be helpful for the treatment of BRC-induced drug-resistant prolactinomas.

[Scientific, transparent and applicable rankings of Chinese pathological guidelines and consensus published in the medical journals in 2022].

The STAR tool was used to evaluate and analyze the science, transparency, and applicability of Chinese pathology guidelines and consensus published in medical journals in 2022. There were a total of 18 pathology guidelines and consensuses published in 2022, including 1 guideline and 17 consensuses. The results showed that the guideline score was 21.83 points, lower than the overall guideline average (43.4 points). Consensus ratings scored an average of 27.87 points, on par with the overall consensus level (28.3 points). Areas that scored above the overall level were "conflict of interest" and "working groups", while areas that scored below the overall level were "proposals", "funding", "evidence", "consensus approaches" and "accessibility". To sum up, the formulation of pathology guidelines and consensuses in 2022 is not standardized, and the evidence retrieval process, evidence evaluation methods and grading criteria for recommendations on clinical issues are not provided in the formulation process; the process and method for reaching consensus are not provided, the plan is lacking, and registration is not carried out. It is therefore suggested that guidelines/consensus makers in the field of pathology should attach importance to evidence-based medical evidence, strictly follow guideline formulation methods and processes, further improve the scientific, applicable and transparent guidelines/consensuses in the field, and better provide support for clinicians and patients.

CircOMA1 modulates cabergoline resistance by downregulating ferroptosis in prolactinoma.

PURPOSE: Prolactinomas are one of the most common pituitary neuroendocrine tumors (PitNETs), accounting for approximately 50% of all pituitary tumors. Dopamine agonists are the main treatment for prolactinoma, but a small number of patients are still resistant to pharmacotherapy. Recent discoveries have revealed that ferroptosis is involved in regulating tumor drug resistance. However, the role of ferroptosis in prolactinoma has not been reported. In this study, we aimed to explore the mechanism of a circRNA in ferroptosis in prolactinoma. METHODS: The expression of circOMA1 in prolactinoma tissues was examined by quantitative reverse transcription PCR (qRT-PCR). The biological function of circOMA1 was evaluated in vitro and in vivo. To explore the role of ferroptosis in prolactinoma, we used qRT-PCR and western blotting. Glutamate-cysteine ligase, modifier subunit (GCLM) was predicted to be a direct target gene of miR-145-5p by bioinformatics analysis, which was confirmed by luciferase reporter assays. RESULTS: circOMA1 was overexpressed in drug-resistant prolactinoma tissues compared with sensitive prolactinoma samples. We further found that circOMA1 promoted MMQ cells growth in vivo and in vitro. In addition, GCLM was directly targeted by miR-145-5p and indirectly regulated by circOMA1. Importantly, circOMA1 induced ferroptosis resistance through the increased expression of Nrf2, GPX4, and xCT, and circOMA1 attenuated CAB-induced ferroptosis in MMQ cells in vivo and in vitro. CONCLUSION: The present study demonstrates that circOMA1 attenuates CAB efficacy through ferroptosis resistance and may be a new therapeutic target for the individualized treatment of DA-resistant prolactinoma patients.

[Clinicopathological and molecular features of metaplastic thymoma].

Objective: To investigate the clinicopathological features, and molecular genetic alterations of metaplastic thymoma (MT). Methods: A total of ten MT cases, diagnosed from 2011 to 2021, were selected from the Department of Pathology of Jinling Hospital, Nanjing University Medical School, Nanjing, China for clinicopathological and immunohistochemical (IHC) examination and clinical follow-up. Fluorescence in situ hybridization (FISH), next-generation sequencing (NGS), and YAP1 C-terminus (YAP1-CT) IHC were performed to detect YAP1::MAML2 fusions. Results: There were four males and six females, ranging in age from 29 to 60 years (mean 50 years, median 54 years). Microscopically, all tumors showed a typical biphasic morphology consisting of epithelial components and gradually or abruptly transitioning spindle cell components. The two components were present in varying proportions in different cases. Immunophenotypically, the epithelial cells were diffusely positive for CKpan, CK5/6 and p63. The spindle cells were diffusely positive for vimentin and focally positive for EMA. TdT was negative in the background lymphocytes. Ki-67 proliferation index was less than 5%. YAP1 and MAML2 break-apart FISH analyses showed that all ten cases had narrow split signals with a distance of nearly 2 signal diameters and may be considered false-negative. Using YAP1::MAML2 fusion FISH assays, abnormal fusion signals were observed in all the ten cases. NGS demonstrated YAP1::MAML2 fusions in all eight cases with adequate nucleic acids; in two cases the fusions were detected by DNA sequencing and in eight cases by RNA sequencing. All ten cases of MT demonstrated loss of YAP1 C-terminal expression in epithelioid cells. Conclusions: MT is a rare and low-grade thymic tumor characterized by a biphasic pattern and YAP1::MAML2 fusions. Break-apart FISH assays may sometimes show false-negative results due to the proximity of YAP1 and MAML2, while YAP1 C-terminal IHC is a highly sensitive and specific marker for MT. Loss of YAP1 C-terminal expression can also be used to screen YAP1::MAML2 fusions for possible MT cases.

[Association of SCN2A, ABCB1 and CYP2C19*3 with genetic susceptibility to major depressive disorder].

Objective: Due to genetic factors might increase the risk of depression, this study investigated the genetic risk factors of depression in Chinese Han population by analyzing the association between 13 candidate genes and depression. Methods: 439 depression patients and 464 healthy controls were included in this case-control study. Case group consisted of 158 males and 281 females, aged (29.84±14.91) years old, who were hospitalized in three departments of the affiliated Brain Hospital of Guangzhou Medical University including Affective Disorders Department, Adult Psychiatry Department and Geriatrics Department, from February 2020 to September 2021. The control group consisted of 196 males and 268 females, aged (30.65±12.63) years old. 20 loci of 13 candidate genes in all subjects were detected by MALDI-TOF mass spectrometry. Age difference was compared using the student's t-test, the distributions of gender and genotype were analyzed with Pearson's Chi-square test. The analyses of Hardy-Weinberg equilibrium, allele frequency and the genetic association of depression were conducted using the corresponding programs in PLINK software. Results: PLINK analysis showed that SCN2A rs17183814, ABCB1 rs1045642, CYP2C19*3 rs4986893 and NAT2*5A rs1799929 were associated with depression before Bonferroni correction (χ2=10.340, P=0.001; χ2=11.010, P=0.001; χ2=9.781, P=0.002; χ2=4.481, P=0.034). The frequencies of minor alleles of above loci in the control group were 12.07%, 43.64%, 2.59% and 3.88%, respectively. The frequencies of minor alleles of loci mentioned above in the case group were 17.43%, 35.99%, 5.47% and 6.04%, respectively. OR values were 1.538, 0.726, 2.178 and 1.592, respectively. After 1 000 000 permutation tests using Max(T) permutation procedure, the four loci were still statistically significant, the empirical P-value were 0.002, 0.001, 0.003 and 0.042, respectively. However, only three loci including SCN2A rs17183814, ABCB1 rs1045642 and CYP2C19 rs4986893 had statistical significance after Bonferroni correction, the adjusted P-value were 0.026, 0.018 and 0.035, respectively. Conclusion: SCN2A rs17183814, ABCB1 rs1045642 and CYP2C19*3 rs4986893 were associated with depression's susceptibility in Chinese Han population. The A allele of SCN2A rs17183814 and CYP2C19*3 rs4986893 were risk factors for depression, while the T allele of ABCB1 rs1045642 was a protective factor for depression.

[Expression and diagnostic value of NKX3.1 and NKX2.2 in mesenchymal chondrosarcoma].

Objective: To investigate the immunohistochemical expression of NKX3.1 and NKX2.2 in mesenchymal chondrosarcoma (MC), and to explore the differential diagnostic value of NKX3.1 and NKX2.2 in MC and other types of small round cell malignant tumors. Methods: A total of 12 cases of MC and 97 other small round cell malignant tumors diagnosed in Jinling Hospital, Nanjing University School of Medicine from 2001 to 2020 were collected for NKX3.1 and NKX2.2 immunohistochemical detection. Among them, two kinds of NKX3.1 antibodies [rabbit polyclonal antibody and rabbit monoclonal antibody (EP356)] were used for detection in 12 cases of MC, and one NKX3.1 antibody (rabbit polyclonal antibody) was detected in 97 cases of other small round cell malignant tumors, and the relevant literature was reviewed. Results: The 12 MC patients included 7 females and 5 males, with a mean age of 33 years (14-54 years). Nine cases were from bone and three from soft tissue. Among the 12 MC patients, 8 patients had postoperative recurrence or metastasis, and 3 of them died of tumor recurrence or metastasis. Histologically, 12 cases of MC showed typical bidirectional differentiation.The positive rate of both NKX3.1 antibodies in MC was 12/12, NKX3.1 was focal weakly positive in only one of 12 chondrosarcomas (grade 3), 5 alveolar rhabdomyosarcomas, 5 embryonal rhabdomyosarcomas, and 5 solitary fibrous tumors, respectively. The remaining 70 cases of other small round cell malignant tumors were negative. The positive rates of NKX2.2 in MC, Ewing sarcoma and olfactory neuroblastoma were 12/12, 15/15 and 4/5, respectively. In 12 cases of chondrosarcoma (grade 3), 5 cases of poorly differentiated synovial sarcoma, 5 cases of alveolar rhabdomyosarcoma, and 5 cases of solitary fibrous tumor, NKX2.2 was focally and weakly positive in only one case, respectively, and all the remaining 50 cases of other small round cell malignant tumors were negative. Conclusions: The expression of NKX3.1 and NKX2.2 proteins are significant indicators in the diagnosis of MC, and the combined detection of NKX3.1 and NKX2.2 can help distinguish MC from most other small round cell malignant tumors.

[Pituicytoma: a clinicopathological analysis of twenty-one cases].

Objective: To investigate the clinicopathological features and treatment strategies of pituicytoma. Methods: Twenty-one cases of pituicytoma were collected at the First Affiliated Hospital of Nanjing Medical University and Jinling Hospital, Nanjing, China from 2009 to 2020. The clinical data of 21 pituicytoma patients was retrospectively analyzed, and the relevant literature was reviewed. Results: Twenty-one patients aged 4 to 68 years, including 8 males and 13 females. All patients underwent surgical treatment. Histologically, the tumor was consisted almost entirely of elongate, bipolar spindle cells arranged in a fascicular or storiform pattern. Mitotic figures were rare. Immunohistochemically, tumor cells were diffusely positive for S-100 protein (21/21), vimentin (15/15) and TTF1 (14/14), while they were weakly or focally positive for GFAP (13/16) and EMA (6/12). CKpan was negative in all cases and Ki-67 proliferation index was low (<5%). Among the 18 patients with follow-up, all survived and 2 relapsed after surgery. Conclusions: Pituicytoma is a rare low-grade glioma of the sellar area. It is easily confused with other sellar tumors. Preoperative diagnosis is difficult. It needs to be confirmed by histopathology and immunohistochemistry. Microsurgery is the main treatment method at present.

[Succinate dehydrogenase-deficient renal cell carcinoma:a clinicopathological, ultrastructural and molecular analysis].

Objective: To investigate the clinicopathological features, immunophenotype, ultrastructure, genetic alterations and prognosis of succinate dehydrogenase-deficient renal cell carcinoma (SDH RCC). Methods: A total of 11 SDH RCCs, diagnosed from 2010 to 2019, were selected from the Department of Pathology of Nanjing Jingling Hospital, Nanjing University School of Medicine for clinicopathologic, immunohistochemical (IHC), ultrastructural investigation and follow-up. The molecular features of seven cases were analyzed by the panel-targeted DNA next generation sequencing (NGS). Results: There were seven males and four females, with ages ranging from 24 to 62 years (mean 41.4 years, median 41 years). Microscopically, SDH RCC was mainly composed of solid and tubular structures with local cystic change. Four cases showed nested or trabecular structure distributed in a loose hypocellular connective tissue or around scar, similar to oncocytoma. The neoplastic cells demonstrated flocculent eosinophilic cytoplasm with typical intracytoplasmic vacuoles. Immunohistochemically, eight cases were negative for SDHB; three cases showed focal and weak expression, whereas normal renal tubular and vascular endothelial cells demonstrated strong cytoplasmic staining. NGS of DNA targeted-panel detected pathogenic mutations of SDHB gene in seven cases (including three cases with equivocal IHC expression of SDHB), without any mutations in other SDH related genes. There were four cases of SDHB missense mutation, one case of frameshift mutation, one case of splicing mutation, and one case of acquired stop codon mutation. Conclusions: SDH RCC is a distinct variant of RCCs with genetic tendency or with hereditary cancer syndrome. NGS is recommended to detect the related gene mutations for a definitive diagnosis. The patients should be closely followed up.

[Anaplastic lymphoma kinase-translocation renal cell carcinoma: clinical and pathological analysis].

Objective: To investigate the clinicopathological features, molecular characteristics, differential diagnosis and prognosis of anaplastic lymphoma kinase (ALK)-translocation renal cell carcinoma. Methods: Two cases of ALK-translocation renal cell carcinoma diagnosed from January 2011 to December 2020 were retrospectively analyzed to characterize their morphological features, immunohistochemical expression and prognosis. Multiple molecular studies including fluorescence in situ hybridization (FISH), reverse transcriptase-polymerase chain reaction (RT-PCR), and next-generation sequencing were performed to characterize the genetic alterations. Results: Two patients included one male and one female, with 59 and 57 years old, respectively. Morphologically, case 1 resembled collecting duct carcinoma or renal medullary carcinoma, which demonstrated tubular, microcapsule and reticular structures, with a remarkable myxoid background and lymphocytes infiltration; case 2 resembled Xp11.2 translocation renal cell carcinoma or type 2 papillary renal cell carcinoma, which demonstrated tubular papillary and focal solid structures, with flocculent cytoplasm and many foamy histiocytes, but without myxoid background and lymphocytes infiltration. Immunohistochemistry showed strongly positive expression of ALK. CK7, E-cadherin, vimentin, PAX8 and CD10 showed various degrees of expression, and other antibodies were nonreactive. A variety of molecular assays showed definite ALK gene translocation, with rare VCL-ALK gene fusion (VCL exon and 16-ALK exon 20) in case 1, and EML4-ALK gene fusion (EML4 exon and 2-ALK exon 20) in case 2. Conclusions: ALK-translocation renal cell carcinoma is rare with various morphological features, and is easy to miss and misdiagnose. The characteristic ALK expression and molecular detection of ALK translocation are helpful for diagnosing this type of renal cell carcinoma.

[Papillary renal neoplasm with reverse polarity: a clinicopathological analysis].

Objective: To study the clinical pathological characteristics, immunophenotype, molecular changes and prognosis of the papillary renal neoplasm with reverse polarity (PRNRP). Methods: Nine cases of PRNRP, diagnosed from 2013 to 2019, were retrieved from the Department of Pathology of Nanjing Jinling Hospital, Nanjing University School of Medicine. Histomorphology, immunophenotype and molecular genetics were analyzed with review of the literatures. Results: There were five male and four female patients, aged from 49 to 70 years, with an average age of 60.1 years. During a mean follow-up of 29 months, one patient died for other cause, and the others survived without disease. Microscopically, the tumor cells arranged in papillary structure with a fibrovascular core, the surface of which was covered with a single layer of cuboidal or columnar cells. The most prominent feature was that the tumor nuclei located at the top of the cytoplasm far from the basement membrane, and they were monotonous in size and arranged neatly with no or few nucleoli. Immunohistochemically, all nine cases of PRNRP showed diffuse positive expression of CK7 and E-cadherin, various degrees of P504s expression, and no expression of CD10 and CD117, with a Ki-67 index of 1%-3%. Unlike other papillary renal cell carcinoma, the nine cases of PRNRP all showed characteristic positive expression of GATA3. The fluorescence in situ hybridization assay showed that the majority of PRNRPs (8/9) did not have triploids on chromosomes 7 and 17. The sequencing of the KRAS gene confirmed the presence of a nonsense KRAS mutation in 8 of the 9 cases. Conclusions: PRNRP is a subtype of papillary renal cell carcinoma with characteristic morphological, immunophenotypic and molecular features, and indolent behaviors. More data are needed to define PRNRP as "carcinoma", and a definitive diagnosis of PRNRP is of great significance for proper treatment choice and accurate prognostication.

[Expression of SS18-SSX fusion-specific antibody and SSX C-terminal antibody in synovial sarcoma and its diagnostic value].

Objective: To investigate the expression and diagnostic value of SS18-SSX fusion-specific antibody and SSX C-terminal antibody in synovial sarcoma (SS). Methods: Immunohistochemical (IHC) EnVision method was used to detect the expression of SS18-SSX fusion-specific antibody and SSX C-terminal antibody in 51 genetically confirmed cases of SS and 94 non-SS tumors diagnosed at Nanjing Jinling Hospital from August 2013 to December 2020. Results: IHC staining for SS18-SSX fusion-specific antibody revealed strongly diffuse nuclear staining in 48 of 51 (48/51, 94.1%) SS cases, whereas none of the 94 non-SS tumors showed any staining. IHC staining for SSX C-terminal antibody showed strongly diffuse nuclear staining in all 51 (51/51, 100%) SS cases; six of the 94 (6/94, 6.4%) non-SS tumors showed variable staining, including two cases each of leiomyosarcoma and fibrosarcoma, and one case each of malignant peripheral nerve sheath tumor and embryonal rhabdomyosarcoma. The sensitivity and specificity of SS18-SSX fusion-specific antibody in diagnosing SS were 94.1% and 100% and these of SSX C-terminal antibody were 100% and 93.6%, respectively. Conclusions: SS18-SSX fusion-specific antibody and SSX C-terminal antibody are highly sensitive and specific markers for SS. Immunohistochemistry using these antibodies may replace FISH or molecular genetic testing in most cases.

[Clinicopathological and molecular features of biphenotypic sinonasal sarcoma].

Objective: To study the clinicopathologic features, immunophenotype, molecular genetics and differential diagnosis of biphenotypic sinonasal sarcoma (BSNS), and to evaluate the role of PAX3 and PAX8 immunohistochemical (IHC) antibodies in the diagnosis of BSNS. Methods: Nasal sinus spindle cell tumors surgically treated at the Jinling Hospital from 2000 to 2019 were collected, including three cases of BSNS, 10 cases of acinar rhabdomyosarcoma, eight cases of schwannoma, five cases of hemangiopericytoma, three cases of fibrosarcoma, and one case of triton tumor. The cases were evaluated by histology, IHC by EnVision for PAX3 and PAX 8 (including PAX8 murine monoclonal antibody, clone number OTI6H8, hereinafter referred to as PAX8-OTI6H8 antibody; PAX8 rabbit monoclonal antibody, clone number EP298, hereinafter referred to as PAX8-EP298 antibody) molecular genetic tests. Results: All three BSNS patients were elderly women with clinical manifestations of nasal congestion and bleeding. Imaging showed a soft tissue density shadow of the nasal cavity and sinuses with bone destruction. The boundaries of tumors which were covered with ciliated columnar epithelium were unclear, and mucosal invasion and squamous metaplasia could be seen. Tumor cells were spindle-shaped, arranged in a bundle-like, braided arrangement, with little cellular atypia and occasional atypical mitotic figures. The tumoral interstitial vessels were mostly thin-walled, some showing staghorn-like changes. There was focal striated muscle differentiation in two cases, and bone invasion was seen in two cases. IHC staining showed that all three cases of BSNS expressed PAX3 and PAX8-OTI6H8, but not PAX8-EP298. All eight cases of schwannoma, five cases of hemangiopericytoma, and one case of triton tumor did not express PAX3, PAX8-OTI6H8 or PAX8-EP298. Eight of the ten cases of alveolar rhabdomyosarcoma expressed PAX3 and PAX8-OTI6H8, but not PAX8-EP298. Three cases of fibrosarcoma showed weak PAX3 and PAX8-OTI6H8 expression, but there was no PAX8-EP298 expression. FISH detection showed that PAX3 break apart in the tumor cells from all three patients (four specimens). Conclusions: BSNS is a distinct sinonasal low grade malignancy with dual differentiation which could be readily confused with a variety of spindle cell tumors encountered in the sinonasal cavity. The molecular genetics of PAX3 gene break is the gold standard for diagnosis of this tumor. IHC marker monoclonal PAX3 is 100% expressed in BSNS, while the specificity is limited. PAX8-OTI6H8 is also expressed in BSNS due to the cross reaction with PAX3 antibody, while PAX8-EP298 is all negative for these tumors.

[Expression of NR4A3/NOR-1 in acinic cell carcinoma of the salivary gland].

Objective: To investigate the diagnostic role of NR4A3/NOR-1 immunohistochemistry in acinic cell carcinoma (AciCC) of the salivary gland. Methods: A total of 142 tumors were collected from 2004 to 2020 at Nanjing Jinling Hospital, including 24 cases of AciCCs, 12 salivary gland secretory carcinomas,14 salivary duct carcinomas,16 adenoid cystic carcinomas,3 basal cell carcinomas,13 mucoepidermoid carcinomas,7 myoepithelial carcinomas,15 pleomorphic adenomas,15 warthin tumor, 8 myoepithelioma,8 basal cell adenomas, and 7 oncocytomas; 28 normal salivary gland tissues and 2 pancreatic AciCC were also included. Results: NR4A3/NOR-1,a nuclear marker,was positive in 91.7% (22/24) of AciCC of the salivary gland,while DOG1,a membranous and cytoplasmic marker, demonstrated a sensitivity of 95.8% (23/24);there was no significant difference in the overall positive rates(P=0.551), but the stain pattern was different. NR4A3/NOR-1 was negative in normal salivary gland tissues and any other types of tumors in the salivary gland; however,DOG1 showed apical staining in the acinar cells in the salivary gland,as well as salivary gland secretory carcinomas,adenoid cystic carcinomas,basal cell carcinomas,mucoepidermoid carcinomas,myoepithelial carcinomas and basal cell adenomas(P<0.001). NR4A3/NOR-1 showed a high sensitivity(91.7%) and specificity(100%) to identify AciCC of the salivary gland,and in combination with DOG1, the sensitivity increased to 100%. Furthermore, NR4A3/NOR-1 were only positive for AciCC arising from salivary glands but not pancreas(0/2)(P=0.018). Conclusion: NR4A3/NOR-1 is a special and sensitive biomarker for AciCC of salivary glands; combined NR4A3/NOR-1 and DOG1 can be an ideal diagnostic immunohistochemical panel for AciCC.

[Expression of H3.3 G34W mutant-specific antibody in giant cell tumors of bone and its diagnostic value].

Objective: To investigate the expression of H3.3 G34W mutant-specific antibody in giant cell tumors of bone (GCTB), and its value in the diagnosis of GCTB. Methods: Immunohistochemical (IHC) EnVision method was used to detect the expression of H3.3 G34W mutant-specific antibody and p63 in 83 GCTBs, 18 aneurysmal bone cysts, 23 chondroblastomas and 28 osteosarcomas diagnosed at Nanjing Jinling Hospital from June 2001 to April 2019. Results: Among the 83 cases of GCTB, 69 cases (69/83, 83.1%) expressed H3.3 G34W. H3.3 G34W expression was found exclusively in the mononuclear cell population with strong and diffuse nuclear staining. H3.3 G34W was expressed in 55 of 57 (96.5%) cases of GCTB in long bones, but only 14 of 26 (53.8%) cases of non-long bone GCTB. All recurrent (9/9)/metastatic GCTB (2/2), post-denosumab GCTB (3/3), primary malignant GCTB (3/3) and secondary malignant GCTB (5/5) also expressed H3.3 G34W. H3.3 G34W was negative in all aneurysmal bone cysts and chondroblastomas. H3.3 G34W was positive in 3 of 28(10.7%) cases of osteosarcomas, and giant cell-rich osteosarcoma(GCRO) was the only histological subtype of osteosarcoma that expressed H3.3 G34W. p63 was expressed in 71.1%(59/83) of GCTB, while the positive rates of p63 in aneurysmal bone cysts,chondroblastomas and osteosarcomas were 3/18, 43.5% (10/23) and 21.4% (6/28) respectively. The sensitivity and specificity of H3.3 G34W mutant-specific antibody in the diagnosis of GCTB were 83.1% and 95.7%. Conclusions: H3.3 G34W mutant-specific antibody is a highly sensitive and specific marker for GCTB and helpful for the diagnosis of GCTB and its variants. The limitation of this antibody is that as a mall number of GCTB harbor G34 mutation other than G34W, and thus that cannot be detected. The incidental expression of H3.3 G34W mutant protein in osteosarcoma could be a potential diagnostic dilemma, and the results of H3.3 G34W IHC staining needs careful interpretation.

[Neuronal intranuclear inclusion disease: a clinicopathological study of two cases].

Objective: To investigate the clinical manifestations, imaging features, histopathologic, immunohistochemical (IHC) and ultrastructure features of neuronal intranuclear inclusion disease (NIID). Methods: HE, IHC staining and EM were performed in cases of NIID diagnosed at the Department of Pathology, Jinling Hospital from 2018 to 2019. Results: Two cases were identified, including one male and one female; both patients were 76 years old. They were hospitalized because of nervous system dysfunction. MRI showed abnormal high signal intensity in corticomedullary junction of bilateral frontal lobes (male patient) and bilateral cerebral hemispheres (female patient). Light eosinophilic transparent inclusion bodies were seen in the nuclei of neurons in both rectal mucosa and cutaneous sweat glands, and these were positive for p62 by IHC. By scanning EM, the inclusion bodies in the sweat gland cells nuclei were round membranous structures consisting of 8-18 nm microfilaments. Conclusions: NIID is a rare, multi-system and slowly progressive neurodegenerative disease. Its clinical manifestations are highly diverse and easily misdiagnosed or missed. Neuroimaging can make a preliminary diagnosis. In the past, NIID can only be diagnosed through autopsy, and this study demonstrates that NIID can be confirmed through skin or rectal mucosal biopsy.

[Xp11 neoplasma with melanocytic differentiation: a clinicopathological analysis].

Objective: To investigate the clinical, histologic and immunophenotypic features, genetic alterations and prognosis of the rare Xp11 neoplasm with melanocytic differentiation. Methods: Twenty-one cases were selected from the Department of Pathology, Jingling Hospital, Nanjing University School of Medicine from May 2008 to May 2018. The clinicopathologic, immunohistochemical, molecular analysis and follow-up details were collected. Results: There were 7 males and 14 females, with their ages ranging from 4 to 57 years (mean 32.8 years). The tumors were located in kidney (11 cases), pelvis (three cases), and in pancreas, retroperitoneum, adrenal gland, small intestine, prostate, cervix and appendix (one case each). Microscopically, most tumors shared similar morphology such as purely nested or sheet-like architectures separated by a delicate vascular network, purely epithelioid cells with clear to granular eosinophilic cytoplasm, lacks of papillary structures, spindle cell or fat components, uniform round to oval nuclei with small visible nucleoli, and in most of them (16/21) melanin pigment. Immunohistochemically, all cases showed moderately (2+) or strongly (3+) positive staining for TFE3 and Cathepsin K. HMB45 and Melan A were focally expressed in three of 21 cases, while the remaining cases showed typically moderate(2+) or strong (3+) expression. None of the cases were immunoreactive for SMA, desmin, CKpan, S-100 and PAX8. All cases showed TFE3 rearrangement using fluorescence in-situ hybridization (FISH). Fusion FISH assays detected SFPQ-TFE3 gene fusion in 16 cases, NONO-TFE3 gene fusion in two, ASPL-TFE3 and MED15-TFE3 gene fusions in one case each. Polymerase chain reaction and direct sequencing detected SFPQ-TFE3 gene fusion in nine cases, NONO-TFE3 and MED15-TFE3 gene fusions in one case each. Clinical follow-up was available for 15 patients for 12 to 74 months. Six patients died of the disease; and three had recurrences and/or metastases. Six patients were alive with no evidence of disease after initial resection. Conclusions: Xp11 neoplasm with melanocytic differentiation has unique morphologic, immunophenotypic and genetic characteristics. The tumor is aggressive, and should be differentiated from Xp11 translocation RCC and perivascular epithelioid cell tumor.

[Eosinophilic solid and cystic renal cell carcinoma: clinicopathological analysis and molecular characterization].

Objective: To study the clinicopathological features, immunohistochemical phenotype, molecular changes, differential diagnosis and prognosis of eosinophilic solid and cystic renal cell carcinoma (ESC RCC). Methods: A total of 15 cases were selected from 2005 to 2019 at Nanjing Jinling Hospital,Nanjing University School of Medicine for clinicopathological and immunohistochemical analysis, 10 of which were subject to cancer-associated mutation analysis using targeted next-generation sequencing (NGS) panel. A literature review was also performed. Results: The patients' ages ranged from 15 to 68 years (mean, 33 years). The male-to-female ratio was 1.1∶1.0. During a mean follow-up of 22 months, none of the patients developed tumor recurrence, progression or metastasis. Histologically, the tumors typically demonstrated solid and cystic architectures and the neoplastic cells contained voluminous eosinophilic cytoplasm with prominent granular cytoplasmic stippling. Immunohistochemically, tumor cells in all cases were immunoreactive for CK20. Signal pathway related protein mTOR and S6 were positive in 14/15 and 6/15 cases, respectively. Cathepsin K, Melan A and HMB45 were at least focally positive in 12/15, 6/15 and 2/15 cases, respectively. CK7 and CD10 showed focal immunostain positivity in some cases, while TFE3, TFEB, CA9 and CD117 were negative in all cases. NGS demonstrated TSC1/TSC2 mutations in all tested cases (10/10). Conclusions: ESC RCC is a rare tumor that tends to occur in young patients with an indolent behavior. Diagnosis can be established by its distinct clinical and histopathologic findings, immunohistochemical phenotype and molecular genetics. The tumor may be considered as a new subtype of RCC.