Objective:To investigate the clinicopathological characteristics, immunophenotypes, diagnostic criteria and differential diagnosis of atrophic kidney-like lesion (AKLL).Methods:Three cases of AKLL were collected from April 2021 to October 2023 at the Xiangya Hospital of Central South University, Changsha, Zhejiang Provincial People′s Hospital, Hangzhou and Ningbo Clinical Pathology Diagnosis Center, Ningbo, China. The clinical, morphological, and immunohistochemical characteristics were analyzed. Relevant literature was also reviewed. A targeted DNA-based next-generation sequencing (a panel of 150 genes) was performed on one of the three cases.Results:There were 1 female and 2 males, aged 30, 57, and 17 years (mean 34.6 years), respectively. The lesions were all incidentally identified during physical or imaging examination. Radiologically, they were all presented as a unilateral renal parenchymal mass. Grossly, the maximum diameters of the lesions were 1.8, 4.0, and 6.5 cm (mean 4.1 cm), respectively. The tumor cut-surfaces were sponge-like, multilocular cystic, and solid, respectively. At low magnification, the lesions were well-circumscribed, while a thick fibromuscular capsule was noted in cases 1 and 3. Cases 1 and 2 were composed of thin-walled cysts or follicular like structures of varying sizes, with the cyst wall lined by flattened and atrophic, or hobnail cells. The luminal spaces contained dense eosinophilic secretion and associated calcifications, while some cysts contained discohesive cells floating in the eosinophilic material. The tissue between the cysts showed predominantly small atrophic tubular structures. Case 3 was almost entirely composed of atrophic and collapsed tubular structures with focal cyst formation, imparting a solid sheets growth pattern under low magnification. Immunohistochemical staining revealed that the cyst lining cells and the intracystic floating cells were WT1 positive, PAX8 negative and CK7 negative, while the atrophic renal tubules were WT negative, PAX8 positive and CK7 positive. Targeted next-generation sequencing in case 1 showed no significant genetic abnormalities. All 3 patients underwent partial nephrectomy. No evidence of recurrence or metastasis was found with a follow-up of 17 to 36 months.Conclusions:AKLL is a rare and novel benign renal disease. It is easily misdiagnosed as a renal neoplasm grossly and histologically. Careful morphological observation combined with characteristic immunophenotypes can aid in its diagnosis and differential diagnosis.

Objective:To investigate the clinicopathological characteristics of ossifying fibromyxoid tumor (OFMT) with rare fusion subtypes.Methods:Three cases of OFMT with rare fusion subtypes, diagnosed and consulted in the Zhejiang Hospital, Zhejiang Provincial People′s Hospital, Hangzhou, China and Ningbo Clinical Pathology Diagnosis Center, Ningbo, China from January 2016 to December 2024 were collected. Immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), and targeted RNA sequencing were performed to analyze the immunohistochemical and molecular genetic characteristics of these OFMT. Literature review was also conducted.Results:All three patients were male, with ages of 50, 74, and 58 years, respectively. The tumors were located in the left foot, left thigh, and left lumbar region, respectively, and all presented as slowly growing, painless masses in the skin or subcutaneous tissue. Grossly, the tumors measured 3.5 cm, 6.3 cm, and 5.0 cm in maximum diameter, respectively, with a grayish-white to grayish-yellow, solid, lobulated cut surface. One case exhibited a noticeable myxoid texture. Microscopically, one tumor was located in the superficial dermis, while the other two were in the subcutaneous tissue. The tumors were well-demarcated and showed a lobulated or multinodular growth pattern. None of the cases had a complete surrounding bony shell (only one case had very focal ossification). The tumor cells were monomorphic, short spindle-shaped, oval to epithelioid, and arranged in solid sheets, trabeculae, and small nests within a variably fibromyxoid stroma. Case 1 exhibited abundant pseudorosette-like structures formed by short spindle cells surrounding acellular fibrous stroma. Case 2 showed focal transition of epithelioid tumor cells into fasciculately arranged spindle cells, with extensive stromal hyalinization. Case 3 had a predominantly myxoid stroma with a rich network of thin-walled blood vessels. The tumor cells exhibited mild nuclear atypia with 1-3 mitotic figures per 50 high-power fields. All three cases showed diffuse and strong expression of CD10. Two of the three cases showed nuclear expression of TFE3, while one case showed diffuse and strong expression of desmin and S-100. Targeted RNA sequencing revealed PHF1 (ex12)::TFE3 (ex7) fusion in two cases and MEAF6 (ex5)::PHF1 (5′UTR) fusion in one case, which were further confirmed by FISH study. All three patients underwent tumor resection. Two showed no recurrence during follow-up periods of 98 months and 15 months, respectively, while one experienced local recurrence at 12 months postoperatively.Conclusions:OFMT with rare fusion subtypes often exhibits atypical histological and immunophenotypic features, and lacks a characteristic bony shell. Incorporating TFE3 into the diagnostic IHC panel greatly aids in screening for the cases with rare PHF1::TFE3 fusions. Familiarity with the histological and immunophenotypic characteristics, and differential diagnostic points of these rare OFMT subtypes, is essential for judicious use of molecular genetic tools in achieving a definitive diagnosis.

Objective:To investigate the clinicopathological characteristics, immunophenotypes, diagnostic criteria and differential diagnosis of atrophic kidney-like lesion (AKLL).Methods:Three cases of AKLL were collected from April 2021 to October 2023 at the Xiangya Hospital of Central South University, Changsha, Zhejiang Provincial People′s Hospital, Hangzhou and Ningbo Clinical Pathology Diagnosis Center, Ningbo, China. The clinical, morphological, and immunohistochemical characteristics were analyzed. Relevant literature was also reviewed. A targeted DNA-based next-generation sequencing (a panel of 150 genes) was performed on one of the three cases.Results:There were 1 female and 2 males, aged 30, 57, and 17 years (mean 34.6 years), respectively. The lesions were all incidentally identified during physical or imaging examination. Radiologically, they were all presented as a unilateral renal parenchymal mass. Grossly, the maximum diameters of the lesions were 1.8, 4.0, and 6.5 cm (mean 4.1 cm), respectively. The tumor cut-surfaces were sponge-like, multilocular cystic, and solid, respectively. At low magnification, the lesions were well-circumscribed, while a thick fibromuscular capsule was noted in cases 1 and 3. Cases 1 and 2 were composed of thin-walled cysts or follicular like structures of varying sizes, with the cyst wall lined by flattened and atrophic, or hobnail cells. The luminal spaces contained dense eosinophilic secretion and associated calcifications, while some cysts contained discohesive cells floating in the eosinophilic material. The tissue between the cysts showed predominantly small atrophic tubular structures. Case 3 was almost entirely composed of atrophic and collapsed tubular structures with focal cyst formation, imparting a solid sheets growth pattern under low magnification. Immunohistochemical staining revealed that the cyst lining cells and the intracystic floating cells were WT1 positive, PAX8 negative and CK7 negative, while the atrophic renal tubules were WT negative, PAX8 positive and CK7 positive. Targeted next-generation sequencing in case 1 showed no significant genetic abnormalities. All 3 patients underwent partial nephrectomy. No evidence of recurrence or metastasis was found with a follow-up of 17 to 36 months.Conclusions:AKLL is a rare and novel benign renal disease. It is easily misdiagnosed as a renal neoplasm grossly and histologically. Careful morphological observation combined with characteristic immunophenotypes can aid in its diagnosis and differential diagnosis.

Objective:To investigate the clinicopathological characteristics of ossifying fibromyxoid tumor (OFMT) with rare fusion subtypes.Methods:Three cases of OFMT with rare fusion subtypes, diagnosed and consulted in the Zhejiang Hospital, Zhejiang Provincial People′s Hospital, Hangzhou, China and Ningbo Clinical Pathology Diagnosis Center, Ningbo, China from January 2016 to December 2024 were collected. Immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), and targeted RNA sequencing were performed to analyze the immunohistochemical and molecular genetic characteristics of these OFMT. Literature review was also conducted.Results:All three patients were male, with ages of 50, 74, and 58 years, respectively. The tumors were located in the left foot, left thigh, and left lumbar region, respectively, and all presented as slowly growing, painless masses in the skin or subcutaneous tissue. Grossly, the tumors measured 3.5 cm, 6.3 cm, and 5.0 cm in maximum diameter, respectively, with a grayish-white to grayish-yellow, solid, lobulated cut surface. One case exhibited a noticeable myxoid texture. Microscopically, one tumor was located in the superficial dermis, while the other two were in the subcutaneous tissue. The tumors were well-demarcated and showed a lobulated or multinodular growth pattern. None of the cases had a complete surrounding bony shell (only one case had very focal ossification). The tumor cells were monomorphic, short spindle-shaped, oval to epithelioid, and arranged in solid sheets, trabeculae, and small nests within a variably fibromyxoid stroma. Case 1 exhibited abundant pseudorosette-like structures formed by short spindle cells surrounding acellular fibrous stroma. Case 2 showed focal transition of epithelioid tumor cells into fasciculately arranged spindle cells, with extensive stromal hyalinization. Case 3 had a predominantly myxoid stroma with a rich network of thin-walled blood vessels. The tumor cells exhibited mild nuclear atypia with 1-3 mitotic figures per 50 high-power fields. All three cases showed diffuse and strong expression of CD10. Two of the three cases showed nuclear expression of TFE3, while one case showed diffuse and strong expression of desmin and S-100. Targeted RNA sequencing revealed PHF1 (ex12)::TFE3 (ex7) fusion in two cases and MEAF6 (ex5)::PHF1 (5′UTR) fusion in one case, which were further confirmed by FISH study. All three patients underwent tumor resection. Two showed no recurrence during follow-up periods of 98 months and 15 months, respectively, while one experienced local recurrence at 12 months postoperatively.Conclusions:OFMT with rare fusion subtypes often exhibits atypical histological and immunophenotypic features, and lacks a characteristic bony shell. Incorporating TFE3 into the diagnostic IHC panel greatly aids in screening for the cases with rare PHF1::TFE3 fusions. Familiarity with the histological and immunophenotypic characteristics, and differential diagnostic points of these rare OFMT subtypes, is essential for judicious use of molecular genetic tools in achieving a definitive diagnosis.

Objective:To investigate the clinicopathological characteristics, and prognosis of appendiceal goblet cell adenocarcinoma(GCA).Methods:The clinical and pathological data of 21 GCA cases were retrospectively analyzed, and their pathological morphology, immunohistochemical phenotype, genetic alteration and clinical treatment and prognosis were studied.Results:Most of the 21 patients showed appendicitis, with appendectomy alone or extensive resection of the tumor, followed by chemotherapy. There were 12 low-grade and 9 moderate and high-grade patients by pathological examination, and tumor cells express CEA, CK20, SATB-2, Syn(19/21), CgA(18/21), CD56(18/21), Ki67(+,10%-50%),and one patient had mutations in the BRAF gene.Depth of tumor infiltration ( r=0.716, P<0.001), and TNM stage ( r=0.816, P<0.001) were all positively correlated with the grade of GCA. After 19 to 98 months of follow-up, one patient relapsed and one patient died. Conclusions:Appendiceal GCA is a kind of tumor with bidirectional differentiation characteristics. Its morphology and biological behavior lineage are relatively broad, especially the high level is more aggressive, hence more active treatment should be adopted.

Human milk plays an irreplaceable role in nutrition, immune promotion and psychological development of infants.And it can also decrease the risk of infectious disease, overweight/obesity, diabetes and other diseases.Therefore, the guidelines of various countries advocate that human milk is the optimal choice for infants.However, cases of food allergy in infants fed with human milk are common in clinical practice.Some studies have found that there are some active food antigens in human milk, which can stimulate immune responses and cause allergic symptoms in infants.At present, the mechanism of food allergy in infants fed with human milk is not clear, and this paper is to review the progress in this field in recent years.

Objective: To investigate the molecular genetic and clinicopathologic characteristics, immunophenotypes, diagnostic and differential diagnostic features of myxoid angiomatoid fibrous histiocytoma (MAFH). Methods: Three cases of MAFH were collected from the archives of Zhejiang Provincial People′s Hospital between January 2015 to August 2018. The clinical and radiologic features, histomorphology, immunohistochemistry, molecular genetics and prognosis were analyzed. Results: Patients consisted of 2 women and 1 man aged 37 years, 46 years, and 57 years, respectively. The clinical manifestations of 3 patients were presented as a painless, slowly-enlarged mass with a duration ranging of 2 weeks, 2 months and 50 years. These tumors were located at the deep somatic soft tissue of extremities or limbs (right hip, left forearm, left wrist, respectively) and 2 were preoperatively considered as ganglion cyst or giant cell tumor of tendon sheath by imaging examinations. The diameter of circumscribed mass lesion was ranged from 3.0 to 7.5 cm, which exhibited a gray white to tan and gelatinous cut surface. Extensive hemorrhage and cystic changes were observed in 2 cases. Under low magnification, all tumors showed a dense fibrous pseudo-capsule with a peritumoral lymphoplasmacytic cuff and a multi-nodular growth pattern. Blood-filled cystic spaces were observed in 2 tumors. The myxoid stroma occupied 60.0%, 80.0% and 90.0% area of the entire tumor, respectively. Within the myxoid areas, tumor cells were oval to stellate and arranged in cord-like, microcystic and reticular growth patterns. Transitions of myxoid tumor components to more solid areas with typical histology of angiomatoid fibrous histiocytoma (AFH) were observed at least focally in all the three cases. The tumor cells exhibited minimal atypia and scarce mitoses (1 to 2/50 HPF) without necrosis, and prominently focal intracytoplasmic vacuoles were identified in one case. The results of immunohistochemistry staining showed that, 2/3 cases focally expressed desmin, 2/3 focally expressed epithelial membrane antigen (EMA), and 1/3 focally expressed CD99. The positive index of Ki67 was approximately 1% to 5%. Fluorescence in situ hybridization analysis showed that EWSR1 gene rearrangement occurred in all of the three cases. During the period of follow-up, one case showed local recurrence at 15 months, one case showed postoperative recurrence at 24 months, and the recurrent tumor slowly grew for 120 months until the second resection, without recurrence at the following 2 months. The left case showed a disease-free survival at 32 months. Conclusions MAFH is a rare subtype of AFH with a low-grade behavior and may lead to diagnostic confusions. Carefully searching for the typical AFH histomorphology and combining with EWSR1 gene rearrangement test can help to distinguish MAFH from other mimickers.

Objective:To investigate the clinicopathological characteristics and molecular genetics of atypical renal cysts.Methods:Six cases of atypical renal cysts were collected from Zhejiang Provincial People′s Hospital, Hangzhou, China, between February 2014 and February 2019. The clinicopathological characteristics and disease progression were analyzed. The 3p deletion and trisomy of chromosomes 7 and 17 were detected using fluorescence in situ hybridization (FISH).Results:All of the 6 patients were male, aged 43-63 years (median: 52 years). Preoperative Bosniak classification showed 4 cases of grade Ⅱ, 1 case of grade Ⅰ and 1 of grade Ⅲ. Histologically, atypical renal cysts appeared as unilocular or multilocular cysts, lined by multilayered flattened or cuboidal-shaped clear or eosinophilic cells. They often showed short papillary projections, and lacked solid or nodular growth of the lesional cells within the wall or septa of the cysts. Histologically, these cysts could be classified into three categories: acquired cystic disease-associated renal cell carcinoma (ACKD-RCC)-like (3 cases), clear cell type (2 cases), and eosinophilic papillary type (1 case). Two cases of ACKD-RCC-like atypical renal cysts were accompanied by clear cell renal cell carcinomas. On immunohistochemical staining, ACKD-RCC-like atypical renal cysts were focally CK7+/AMACR+/CD57+, the clear-cell type atypical renal cysts were CK7+/CAⅨ+, and eosinophilic papillary type atypical renal cysts were CK7+/AMACR+. FISH analyses showed that one case of ACKD-RCC-like atypical renal cysts had trisomy 17 and one case of clear cell type had 3p deletion, while no signal abnormality was detected in the other cases. The six patients were followed up for 13 to 70 months (median: 27 months), and no evidence of renal cell carcinoma was noted.Conclusion:Atypical renal cysts are a group of lesions that are heterogeneous in clinical, histological and immunophenotypical and molecular genetic features. FISH analyses suggest that a subset of the cases may be precursors of currently known renal cell carcinomas. Extensively sampling and careful observation of the histological characteristics of the cyst wall are important for distinguishing atypical renal cysts from extensively cystic renal cell carcinomas.

Objective: To investigate the clinicopathologic characteristics, immunophenotypes, and differential diagnostic features of extra-pleural solitary fibrous tumor (SFT) with uncommon histology. Methods: Seven cases of extra-pleural SFT with uncommon histology were collected during January 2015 and December 2016 in Zhejiang Provincal People′s Hospital; the clinical and radiologic features, histomorphology, immunophenotype and prognosis were analyzed. EnVision method was used for immunohistochemical staining of STAT6, CD34 and other differential diagnosis associated markers. Results: There were five male and two female patients, age from 23 to 54 years (mean=39 years). Three tumors were located in the soft tissue of head and neck, two in trunk subcutaneous soft tissue, one in sella region, and one in the kidney. Grossly the tumors ranged from 0.4 to 8.0 cm (mean=3.1 cm). Microscopically, all three head and neck cases resembled giant cell angiofibroma/giant cell subtype SFT, and one case showed sheet-like pattern of the multinucleated syncytial cells, creating a biphasic arrangement similar to myofibroma. Both truncal tumor resembled lipomatous type SFT, with one similar to dermatofibrosarcoma protuberans and the other to atypical spindle cell lipomatous tumor. The sella tumor showed morphology of a conventional SFT with high grade sarcomatous transformation. The renal tumor demonstrated a malignant SFT with entrapped benign renal tubules, mimicking a biphase synovial sarcoma or a malignant mixed epithelial and stromal tumor. By immunohistochemistry, all seven SFTs showed diffuse and strong nuclear reactivity to antibody against STAT6. Conclusions Extra-pleural SFTs show a significant heterogeneity of morphology and biological behavior which could cause differential confusion.Careful attention to its characteristic histomorphology with the use of STAT6 immunohistochemistry can help distinguish this tumor from its many mimickers.

Objective: To investigate the clinicopathologic characteristics, immunophenotype, differential and diagnostic features of atypical spindle cell lipomatous tumor (ASLT). Methods: Three cases of ASLT were collected from January 2010 to March 2017 at Zhejiang Provincial People′s Hospital. The clinical and imaging features, histomorphology, immunophenotype and prognosis were analyzed. Fluorescence in situ hybridization (FISH) was used to detect MDM2 gene amplification, and relevant literature was reviewed. Results: All three patients were adult males, aged 38, 43 and 54 years, respectively. One tumor originated in the subcutaneous soft tissue in the head and neck, one was located in the left primary bronchus and one in the latissimus dorsi muscle. Grossly, all three tumors were circumscribed and ranged from 4.0 to 5.8 cm in size. Microscopically, all showed a focally infiltrative front. These tumors were composed of variable proportions of spindle-shaped and adipocytic cells in a background of variable fibrous and edematous matrix. Scattered lipoblasts were easily seen. One tumor was composed predominately of spindle tumor cells, one of adipocytic cells, and one of equally mixed cell populations. The spindle tumor cells were generally bland-appearing with focal nuclear enlargement and hyperchromasia noted in one case. Mitosis was not seen in neither the spindle cells nor the adipocytic cells. By immunohistochemistry, diffuse and strong reactivity to CD34 of the spindle cells was noted in all cases, definite loss of Rb expression was noted in one of three cases, and S-100 protein was expressed only in the adipocytic cells. INI-1 was intact and Ki-67 index was 1% to 3%. All other markers including CDK4, MDM2, STAT6, SOX10, CD99, bcl-2, β-catenin, CD117, GFAP, CK, EMA, SMA and desmin were negative. FISH of MDM2 was done in two cases, and both showed no amplification. The ASLT in the head and neck had two recurrences during 17 months of follow-up, whereas the tumor in the latissimus dorsi was free of disease during 33 months of follow-up. Conclusions ASLT is a rare subtype of low-grade adipocytic neoplasm and is distinctive from atypical lipomatous tumor/well-differentiated liposarcoma. The histomorpholgy of ASLT has significant heterogeneity and forms a continuous spectrum. ASLT needs to be distinguished from a series of benign and malignant soft tissue tumors.