Objective:To investigate the clinicopathological and molecular genetic characteristics of well-differentiated/dedifferentiated liposarcoma (WDLPS/DDLPS) with myxoid-like morphology, and to distinguish them from myxofibrosarcoma (MFS) with similar morphology.Methods:Twenty-nine cases of myxoid-like liposarcoma and 5 cases of MFS were collected from Henan Provincial People′s Hospital, Zhengzhou, China and the First Medical Center of PLA General Hospital, Beijing, China from January 2015 to March 2023. Relevant markers were detected using immunohistochemistry and fluorescence in situ hybridization (FISH). The literature was also reviewed.Results:There were 24 males and 10 females, with ages ranging from 41 to 73 years. The tumor sites included retroperitoneum ( n=17), abdomen ( n=9), lower limbs ( n=5), scrotum ( n=1), upper limb ( n=1) and axilla ( n=1). WDLPS was commonly seen as lipomatoid type (12 cases), while the dedifferentiated components of DDLPS included low-grade (13 cases) and high-grade (2 cases) morphology, with low-high grade myxofibrosarcoma, dermatofibrosarcoma protuberans, and low-grade fibrosarcoma structures. Twenty-nine liposarcomas had various proportions of myxoid-like morphology, while 16 showed various degrees of tumor necrosis. The myxoid-like component showed myxoid pleomorphic liposarcoma (MLPS)-like morphology, lobulated growth, characteristic slender, ramified capillary network,"chicken claw-like"morphology, mucus-rich stroma and lung edema-like morphology. Tumor cells were spindle and oval, with many variable vacuolar lipoblasts. MDM2 gene amplification was detected using FISH and present in all tested cases (29/29). DDIT3 break-apart mutation was not detected, but its cluster amplification was present (24/29). Among the MFS cases, one showed cluster amplification (1/5), but no cases showed break-apart or amplification of MDM2 gene. Conclusions:WDLPS/DDLPS with myxoid-like morphology is most commonly seen in the retroperitoneum and abdominal cavity and mostly harbors DDIT3 break-apart probe amplification, while this amplification is not specific to liposarcoma. For core biopsy specimens or very rare tumors in the limbs, when histology has mucinous stroma and MLPS-like morphology, misdiagnosis of MLPS or other non-lipomatous neoplasms with myxoid morphology should be avoided.

The diagnosis of vascular diseases is not only about distinguishing neoplastic or non-neoplastic lesions, but also focusing more on emphasizing the essence of the disease, namely the presence or absence of endothelial cell proliferation, and further to distinguishing true hemangioma tumors or vascular malformation. This article is based on the International Society for the Study of Vascular Anomalies (ISSVA) classification, which is widely used in clinical practice, and discusses the related pathological diagnosis issues of vascular diseases.

Objective:To investigate the clinicopathological features, classification, and genetic characteristics of common lymphatic malformation (CLM) in superficial soft tissue.Methods:A retrospective study of 110 patients with the diagnosis of CLM at the Henan Province People′s Hospital, China from August 2019 to August 2022 was performed. The clinicopathological features, relevant immunohistochemical (IHC) staining results, and fluorescence quantitative PCR of PIK3CA mutation were analyzed, and patients were followed up.Results:Among the 110 CLM patients, there were 53 males and 57 females; 65 cases (65/110, 59.1%) were first detected when the patients were≤2 years old. The most common location was the head and neck in 41 cases (41/110, 37.3%). Clinically, 102 cases (102/110, 92.7%) were solitary, 83 cases (83/110, 75.5%) were skin-colored, 69 cases (69/110, 62.7%) had indistinct borders, and 10 cases (10/110, 9.1%) had diffuse and severe macroscopic manifestations. There were 52 macrocystic type (52/110, 47.3%), 23 microcystic type (23/110, 20.9%), and 35 combined type (35/110, 31.8%). The macrocystic CLM presented as soft, translucent masses with large cystic cavities on the cut surface, and histologically they were composed of large, irregularly dilated channels that were thicker with irregular smooth muscle and lymphocytic infiltration. Microcystic CLM showed wartlike projections or translucent blisters on the skin, with small honeycomb structures on the cut surface, and histologically consisted of round or angular dilated small lymphatic vessels with little or no smooth muscle. The combined CLM had both macrocystic and microcystic morphologies. IHC staining showed that the lymphatic endothelial cells were positive for LYVE-1, D2-40, PROX1, CD31, and VEGFR3 but negative for CD34; in the macrocystic and combined CLM vessel walls were positive for SMA. Eight of 13 CLM had PIK3CA mutation. All patients were followed up, and 24 (24/110, 21.8%) had relapses, which more frequently occurred in combined type, followed by microcystic type.Conclusions:CLM is a congenital vascular malformation composed of dilated, abnormal lymphatic channels, with PIK3CA mutation. There are significant differences in clinicopathological characteristics among the different types. Since microcystic and combined CLM are prone to recurrence, accurate pathological subtyping is necessary to guide treatment and to predict prognosis.

Objective:To investigate the clinicopathological features, molecular genetic features, and differential diagnosis of intraductal carcinomas (IDC) of the salivary glands.Methods:Twenty-five cases of salivary gland IDC diagnosed at the Department of Oral Pathology, Shanghai Ninth People′s Hospital and two cases from Department of Pathology, Henan Provincial People′s Hospital, Zhengzhou, China from January 2008 to July 2023 were collected. Their clinical and pathological features were analyzed retrospectively. Fluorescence in situ hybridization and Sanger sequencing were performed. The patients were followed up and related literatures were reviewed.Results:There were 27 patients with IDC, including 15 males and 12 females, ranging in age from 20.0 to 80.0 years (mean 55.9 years). Clinically, the tumor often presented as a painless mass with a tumor diameter of 1.0-3.0 cm (mean 2.0 cm). All patients received surgical treatment. Twenty patients were followed up. One of them (1/20) died of lung cancer, while the rest survived without tumor recurrence. Histologically, IDC were classified as: intercalated (63.0%, 17/27), apocrine (25.9%, 7/27), oncocytic (7.4%, 2/27) and mixed (3.7%, 1/27) types. Intercalated tumors showed positive S-100 and negative androgen receptor (AR) immunoreactivity. Ki-67 proliferation index was low (about 1%-5%). Nine cases had the RET gene disruption, and 2 cases showed the BRAF V600E mutation. Apocrine tumors showed strong AR immunoreactivity but no S-100 immunoreactivity. Ki-67 proliferation index was high (about 10%-60%), and the RET gene rupture was detected in 1 case. Oncocytic tumors were similar to that of intercalated type in 2 cases, and RET gene disruption was detected in the both cases. Mixed tumors showed histologic features of oncocytic and apocrine patterns and harbored the RET gene disruption.Conclusions:IDC is a rare low-grade malignant tumor of the salivary gland and easily confused with other salivary gland tumors with similar morphology. Molecular testing is helpful for its differential diagnosis.

Objective:To investigate the clinicopathological features and genevariation of sporadic arteriovenous malformation (AVM) in soft tissue.Methods:Eighty cases of soft tissue sporadic AVM diagnosed in Henan Provincial People′s Hospital from January 2017 to March 2022, were retrospectively collected. The relevant indicators were detected by immunohistochemistry and fluorescent quantitative PCR, and the relevant literature was reviewed.Results:There were 42 males and 38 females patients, aged from 4 to 71 years, with a mean age of 26 years.The sites of the disease included head and neck (34 cases), limbs (24 upper limbs, 17 lower limbs) and trunk (5 cases). The main clinical manifestations were characteristic pulsation, tremor, temperature rise, local pain, ulcer or repeated bleeding, and heart failure in severe cases due to long-term hemodynamic abnormalities.Color Doppler ultrasound (CDFI) can detect the high flow characteristics of AVM.Multiple cavitary vascular shadows were seen on MRI. Microscopically, the pathological tissue involved the skin appendages, deep fat and muscle tissue, in which abnormal vascular proliferation was seen, mostly scattered, the lumen was irregularly expanded, the wall thickness was different, but most of them were thick, the vascular wall was glassy and myxoid, inflammatory cell infiltration, bleeding, thrombosis and organization were visible, and calcification was rare.Clustered proliferative muscular small vessels were found around the abnormal blood vessels.No vascular endothelial cell proliferation was found in the blood vessels of the lesion. Immunohistochemistry showed that vascular endothelial cells expressed CD31, CD34 and ERG, and muscle fibers and smooth muscle tissues in the wall expressed SMA.Elastic fiber staining showed incomplete elastic layer in the wall of the malformed artery.PIK3CA gene was detected in 15 cases, and 1 case (1/15) had mutation (mutation rate 6.7%). All cases underwent surgical resection, 73 cases were followed up for 3 months to 5 years, and 15 cases recurred.Conclusions:Sporadic AVM in soft tissue is a typical lesion of vascular malformation with high flow velocity. There are abnormal arteries and clusters of proliferating small vessels.Because of the significant difference in clinical manifestation, treatment and prognosis, pathological diagnosis should be distinguished from congenital hemangioma, intramuscular hemangioma capillary type, PTEN soft tissue hamartoma and common venous malformation.Very few cases may involve PIK3CA gene mutation, suggesting that there may be abnormal PI3K signal pathway in AVM and may participate in the occurrence and development of the disease. AVM has a high recurrence rate and needs long-term follow-up.

Objective:To study the clinicopathological, immunophenotypic and molecular genetic characteristics of nodular fasciitis (NF) in unusual sites.Methods:A total of 50 cases of NF diagnosed between January 2015 and January 2021 were reviewed in the Department of Pathology, Henan Provincial People′s Hospital, and the clinical and pathologic data were analyzed. Among them, 14 cases from unusual sites were included in this study. Immunohistochemical (IHC) staining was used to detect the expression of related proteins, and fluorescence in situ hybridization (FISH) was used to detect the breakage of the USP6 gene.Results:There were seven males and seven females in the 14 NF respectively. The lesions were located in the extremities, perineum, breast, wrist joints, the gap between lumbar vertebra 4/5, and in eight cases there was involvement of unusual tissues (six cases in skeletal muscle, one case in nerve root, and one case was intravascular). The tumor boundary was unclear with infiltrating growth. Spindle-shaped myofibroblasts were arranged in bundles or chaotically, with mild pleomorphic, small nucleoli and various mitotic figures. The tumor stroma showed collagenization to myxoid degeneration with erythrocyte extravasation and infiltration of inflammatory cells. IHC staining showed that the spindle cells expressed SMA focally or partially, and p16 diffusely and strongly. FISH showed that 12 of 14 cases had USP6 gene breakage, and two of them occurred in the intrathoracic skeletal muscle with the red signal amplification of USP6 gene.Conclusions:NF in unusual sites shows similar clinicopathological and genetic characteristics to classic NF, but the tumor mostly has infiltrating borders, non-specific and strong expression of p16, and USP6 red signal amplification. The pathological diagnosis of NF in rare sites should be highly vigilant.

Objective:To investigate the clinicopathological features, immunophenotypic and molecular genetic characteristics and differential diagnosis of fibrous hamartoma of infancy (FHI).Methods:Thirty-three cases of surgically removed FHI were collected from the Department of Pathology, Henan Provincial People′s Hospital from October 2011 to December 2020, the clinical and pathologic data with follow-up were collected and analyzed. Next-generation sequencing (NGS) and quantitative real time polymerase chain reaction (q-PCR) were used to study the molecular genetics.Results:The FHI cases occurred in 21 males and 12 females (mean age 16.7 months, range 6 months to 6 years). The sites included trunk ( n=21), limb ( n=11), and neck (n=1). All patients had painless solitary superficial soft tissue masses, the size was 1.5-9.0 cm (mean 3.8 cm). Microscopically, they were composed of mature adipose tissue, fibroblast/myofibroblast bundle and primitive mesenchymal cells in different proportions; giant cell fibroblastoma-like areas were seen in 14 cases. Immunohistochemistry showed variable expression of EGFR in the spindle cells and primitive mesenchymal components. In most cases, the spindle cells were positive for CD34 and SMA; giant cell fibroblastoma-like areas were strongly positive for CD34; and S-100 protein was expressed by adipocytes in all cases. Ki-67 labeling index ranged 1%-5%. There were recurrent somatic EGFR exon 20 insertion/duplication mutations in six cases tested by NGS, and there were three different mutation types: p.Asn771_His773dupAsnProHis, p.Pro772_His773insProProHis, and p.His773_Val774insThrHis. All the above 6 and another 15 tested cases showed EGFR exon 20 insertion/duplication mutations by q-PCR. Conclusions:FHI is a rare benign fibroblast/myofibroblast tumor. The characteristic histologic feature is organoid triphasic morphology, and the molecular feature is somatic mutation of EGFR exon 20 (insertion/duplication).

Objective:To investigate the role of DDX3 up-regulation in the proliferation of human cervical cancer cells and its correlation with clinical prognosis.Methods:Expression levels of DDX3 in the 59 specimens of cervical cancer and adjacent non-neoplastic tissue collected at Henan Provincial People′s Hospital from April 2012 to March 2013 were detected using immunohistochemistry. A lentivirus-mediated DDX3-over-expression cell line was constructed based on HeLa cells of cervical cancer. CCK-8 assay was used to evaluate cell survival rate. Boyden chamber was used to measure the cell migration and invasion. Real-time fluorescence quantitative PCR was used to detect DDX3 expression level and Western blot was used to detect the expression of EMT and PI3K/Akt signal pathway-related proteins. Results:DDX3 overexpression was associated with FIGO stage, depth of cervical invasion and lymph node metastasis ( P<0.05). Kaplan-Meier analysis revealed that cervical cancer patients with high expression of DDX3 had a poor overall survival ( P<0.05). Compared with the cells transfected with pLVX-Con vector, the expression of DDX3 protein and mRNA was significantly increased in the cells transfected with pLVX-DDX3 (all P<0.01). Cell proliferation was significantly increased following transfection with pLVX-DDX3 for 72 h in HeLa cells compared with that transfected with pLVX-Con ( P<0.05). Compared with the controls, DDX3 overexpression significantly promoted the migration and invasion of HeLa cells ( P<0.05), and increased the expression of N-Cadherin, vimentin and Snail in HeLa cells ( P<0.05). In pLVX-DDX3 group, the expression levels of β-catenin, phosphorylated Akt, and pAkt′s downstream target p-GSK3β were significantly higher than those of pLVX-Con group ( P<0.05). The expression levels of p-Akt, p-GSK3β and β-catenin were decreased when the PI3K/Akt pathway was blocked using the PI3K inhibitor LY294002 ( P<0.05), and the expression levels of N-Cadherin, vimentin and Snail were also significantly decreased ( P<0.05). Conclusions:DDX3 overexpression promotes proliferation, migration and invasion of cervical cancer cells, and induces epithelial-mesenchymal transition (EMT). Its mechanism may be related to activation of the PI3K/Akt signaling pathway.

Objective:To investigate the clinicopathological features, and diagnostic and differential diagnostic characteristics of extranodal nasal type natural killer/T-cell lymphoma (ENKTCL) of the digestive system.Methods:Thirteen cases of ENKTCL in the digestive system were collected at the Henan Provincial People′s Hospital, Zhengzhou, China, from August 2000 to August 2020. The histopathological, immunohistochemical and in situ hybridization features were analyzed, as well as those of T-cell receptor (TCR) gene rearrangement in some cases. The patients were followed up.Results:There were 11 males and 2 females. The age ranged from 28 to 80 years (median=53 years). Seven cases were present in the colorectum, and 3 cases were present in the small intestine. The other three cases were in stomach, gallbladder and liver (one case each). The main clinical symptoms were fever, and abdominal pain, often accompanied by fatigue, diarrhea, hematochezia, elevated serum albumin, elevated lactate dehydrogenase, and increased peripheral blood EB virus DNA copy. Histologically, the tumor accompanied by a heavy admixture of inflammatory cells (small lymphocytes, plasma cells and histiocytes). There was diffuse dense tumor cell infiltrate, with prominent coagulative necrosis. The lymphomatous infiltrate had angiocentric and angio-necrotic changes. Immunohistochemically, lymphoid cells expressed CD3 in all cases. Some of them showed weakened/absent other T cell markers, while all of them expressed CD56 except 1 case. A few of the cases showed CD4 -/CD8 + killer T cell phenotypes. In situ hybridization showed EB virus encoded RNA (EBER) was positive in all cases. Clonal TCR gene rearrangement was not detected in all 7 cases tested. The median survival time was 9 months. Conclusions:ENKTCL of the digestive system is extremely rare. It often predisposes the patients to acute abdomen such as perforation of the gastrointestinal tract. The treatment outcomes are dismal, and the prognosis is poor. Clinical and imaging studies are often non-specific. It is also easy to be misdiagnosed as non-specific ulcers. Combined with immunohistochemistry, in situ hybridization and TCR gene rearrangement analysis and better understanding of this tumor′s clinicopathological characteristics can help improve its diagnosis and early treatment.

Objective: To investigate the clinicopathological characteristics, histogenesis, immunophenotypes, molecular genetic characteristics, diagnosis and differential diagnosis of calcifying fibrous tumors (CFT). Methods: A total of 32 cases of CFT (22 cases from Henan Provincial People′s Hospital and 10 cases from PLA Army Medical Center) diagnosed between June 2009 and February 2019 were reviewed. The clinical and pathologic data were analyzed. Results: There were 12 male and 20 female patients, aged from 15 to 63 years (mean 40.8 years). Eleven cases occurred in stomach, four cases in retroperitoneum, four cases in ovary, two cases in scrotum, two cases in mediastinum, two cases in head and neck, one case each in thoracic cavity, lung, adrenal gland, kidney, sigmoid colon, epididymis and mesosalpinx. All the tumors were solid masses with clear boundaries. The maximal dimension of the tumors ranged from 0.6 to 10.0 cm. Microscopically, there was hypocellular stromal sclerosis and wavy storiform coarse collagen with superimposed scattered or patchy lymphocytes and plasma cells; calcification or gravel formation were also detected. Immunohistochemistry showed that spindle cells were positive for vimentin and some were positive for CD34; and they were negative for calponin, SMA, desmin, S-100 protein, SOX10, STAT6, β-catenin, ALK, CD117, DOG1, CKpan, and EMA. No ALK rearrangement was detected by FISH in all cases. No C-KIT and PDGFRA mutation was detected in all the tested 11 cases of stomach, four cases of retroperitoneal and one case of sigmoid colon CFT. MDM2 was not amplified by FISH in all four tested cases of retroperitoneal CFT. Conclusions CFT is a rare benign tumor of fibroblastic cell origin. The diagnosis mainly depends on histomorphologic analysis and immunophenotyping. CFT should be differentiated from other benign and malignant spindle cell mesenchymal tumors.