Left lower lobe sleeve resection for the clear cell variant of pulmonary mucoepidermoid carcinoma: A case report

BACKGROUND

Pulmonary mucoepidermoid carcinoma (PMEC) is a rare malignancy that arises from minor salivary glands within the tracheobronchial tree. The clear cell variant of PMEC is exceptionally uncommon and presents notable diagnostic challenges, primarily attributable to its morphological similarity to other tumors containing clear cells.

CASE SUMMARY

A 22-year-old male, formerly in good health, came in with a two-month duration of persistent cough and production of sputum. Subsequent imaging and bronchoscopy examinations revealed a 2 cm tumor in the distal left main bronchus, which resulted in complete atelectasis of the left lung. Further assessment via positron emission tomography/computed tomography scans and endoscopic biopsy confirmed the primary malignant nature of the tumor, characterized by clear cell morphology in most of the tumor cells. The patient underwent a left lower lobe sleeve resection accompanied by systematic mediastinal lymph node dissection. Molecular pathology analysis subsequently revealed a CRTC3-MAML2 gene fusion, leading to a definitive pathological diagnosis of the clear cell variant of PMEC, staged as T2N0M0. After surgery, the patient experienced a smooth recovery and exhibited no signs of recurrence during the one-and-a-half-year follow-up period.

CONCLUSION

This article describes an unusual case of a clear cell variant of PMEC characterized by the presence of a CRTC3-MAML2 gene fusion in a 22-year-old male. The patient underwent successful left lower lobe sleeve resection. This case underscores the distinctive challenges associated with diagnosing and treating this uncommon malignancy, underscoring the importance of precise diagnosis and personalized treatment strategies.

[Radiation-associated sarcomas of bone and soft tissue: a clinicopathological analysis of 46 cases]

Objective: To investigate the clinical, imaging, histological, and molecular features and the differential diagnosis of radiation-associated sarcomas of bone and soft tissue. Methods: Forty-six cases of radiation-associated sarcomas of the bone and soft tissue in Beijing Jishuitan Hospital from January 2010 to January 2022 were retrospectively analyzed; and the imaging, histological features and immunophenotype were examined. Results: There were 33 females and 13 males, aged from 18 to 74 years, with a mean of 52 years. The most common site of radiation-associated sarcomas were the limbs and spine (15 cases), followed by the chest (9 cases). The primary diseases included epithelial tumors (15 breast cancer, 6 cervical cancer, and 5 bowel cancer), hematolymphoid tumors, bone and soft tissue tumors and infectious lesions. The latent period of radiation-associated sarcomas ranged from 2-22 years, with an average of 11.6 years. Histopathologically, the morphology was divergent from the primary tumor. The most common malignant tumor type was undifferentiated sarcoma (22 cases), followed by osteosarcoma (16 cases). The immunophenotype of radiation-related sarcoma was almost the same as the corresponding soft tissue sarcoma. Conclusions: Radiation-induced sarcoma has a wide range of primary tumor types and its imaging, morphology and immunohistochemical features are similar to those of the primary sarcoma of bone and soft tissue. Clinical correlation is often recommended for the differential diagnosis.

Chronic pulmonary mucormycosis caused by rhizopus microsporus mimics lung carcinoma in an immunocompetent adult: A case report

BACKGROUND

Pulmonary mucormycosis is a rare but life-threatening invasive fungal infection that mostly affects immunocompromised patients. This disease usually develops acutely and progresses rapidly, often leading to a poor clinical prognosis. Chronic pulmonary mucormycosis is highly unusual in immunocompetent patients.

CASE SUMMARY

A 43-year-old man, who was a house improvement worker with a long history of occupational dust exposure, presented with an irritating cough that had lasted for two months. The patient was previously in good health, without dysglycemia or any known immunodeficiencies. Chest computed tomography revealed a mass in the left lower lobe, measuring approximately 6 cm in diameter, which was suspected to be primary lung carcinoma complicated with obstructive pneumonia. Thoracoscopic-assisted left lower lobectomy was performed, and metagenomic next-generation sequencing detection, along with special pathological staining of surgical specimens, suggested Rhizopus microsporus infection. Postoperatively, the patient's respiratory symptoms were relieved, and no signs of recurrence were found during the six-month follow-up.

CONCLUSION

This article reports a rare case of chronic pulmonary mucormycosis caused by Rhizopus microsporus in a middle-aged male without dysglycemia or immunodeficiency. The patient's surgical outcome was excellent, reaffirming that surgery remains the cornerstone of pulmonary mucormycosis treatment.

[Mutation characteristics of osteosarcoma: a single center study of 64 cases using next-generation sequencing]

Objective: To investigate the distribution and characteristics of gene mutations in osteosarcoma, and to analyze the frequency and types of detectable mutations, and to identify potential targets for individualized treatment of osteosarcoma. Methods: The fresh tissue or paraffin-embedded tissue samples of 64 cases of osteosarcoma that were surgically resected or biopsied and then subject to next generation sequencing, were collected from Beijing Jishuitan Hospital, China from November 2018 to December 2021. The tumor DNA was extracted to detect the somatic and germline mutations using targeted sequencing technology. Results: Among the 64 patients, 41 were males and 23 were females. The patient age ranged from 6 to 65 years with a median age of 17 years, including 36 children (under 18 years old) and 28 adults. There were 52 cases of conventional osteosarcoma, 3 cases of telangiectatic osteosarcoma, 7 cases of secondary osteosarcoma, and 2 cases of parosteosarcoma. The detection rate of gene mutations was overall 84.4% (54/64). There were 324 variations in 180 mutated genes, including 125 genes with copy number variations, 109 single nucleotide variants, 83 insertions or deletions, and 7 gene fusions. The most common mutated genes were TP53, VEGFA, CCND3, ATRX, MYC, RB1, PTEN, GLI1, CDK4 and PTPRD. Among them, TP53 had the highest mutation rate (21/64, 32.8%), single nucleotide variant was the main mutation type (14/23, 60.9%), and 2 cases carried the TP53 germline mutation. VEGFA and CCND3 showed copy number amplification simultaneously in 7 cases. Conclusions: The high-frequency mutation of TP53 suggests that it plays an important role in the pathogenesis and development of osteosarcoma. VEGFA, CCND3 and ATRX are mutated genes in osteosarcoma and worthy of further studies. Combination of pathologic diagnosis and next generation sequencing with clinical practice can guide individualized treatment for patients with refractory, recurrent and metastatic osteosarcoma.

Surgical resection of a giant thymolipoma causing respiratory failure: A case report

BACKGROUND

Thymolipoma is a rare benign tumor arising from the anterior mediastinal thymus and is composed of mature fatty tissue and interspersed nonneoplastic thymic tissue. This tumor accounts for only a small percentage of mediastinal masses, and the majority of them are asymptomatic and found incidentally. To date, fewer than 200 cases have been published in the world literature, of which most excised tumors weighed less than 0.5 kg and the largest weighed 6 kg.

CASE SUMMARY

A 23-year-old man presented with a complaint of progressive breathlessness for 6 mo. His forced vital capacity was only 23.6% of the predicted capacity, and his arterial partial pressure of oxygen and carbon dioxide were 51 and 60 mmHg, respectively, without oxygen inhalation. Chest computed tomography revealed a large fat-containing mass in the anterior mediastinum that measured 26 cm × 20 cm × 30 cm in size and occupied most of the thoracic cavity. Percutaneous mass biopsy revealed only thymic tissue without signs of malignancy. A right posterolateral thoracotomy was successfully performed to remove the tumor along with the capsule, and the excised tumor weighed 7.5 kg, which to our knowledge, was the largest surgically removed tumor of thymic origin. Postoperatively, the patient’s shortness of breath was resolved, and the histopathological diagnosis was thymolipoma. No signs of recurrence were observed at the 6-mo follow-up.

CONCLUSION

Giant thymolipoma causing respiratory failure is rare and dangerous. Despite the high risks, surgical resection is feasible and effective.

[Pediatric myofibroma/myofibromatosis of the soft tissue and bone: a clinicopathological analysis of 28 cases]

Objective: To investigate the clinicopathological features, diagnosis and differential diagnosis of pediatric myofibroma/myofibromatosis of the soft tissue and bone. Methods: All cases of pediatric myofibroma/myofibromatosis of the soft tissue and bone diagnosed between January 2011 and December 2018 were retrieved from the surgical pathology records in the Department of Pathology, Beijing Jishuitan Hospital, Beijing, China. Clinical and radiological data were collected. H&E and immunohistochemistry were used to examine histological and immunophenotypic features and to make the diagnosis and differential diagnosis. The relevant literature was also reviewed. Results: Twenty-eight cases of pediatric myofibroma/myofibromatosis of the soft tissue and bone were respectively collected. The patients' ages ranged from 2 months to 14 years, with a mean age of 7 years. There were 7 females and 21 males. There were 12 cases located in soft tissue, including the finger (n=9), upper arm (n=1) and foot (n=2). There were 14 cases located in the bone of limb, including the femur (n=8), tibia (n=4), clavicle (n=2), fibula (n=2) and radius (n=1). There were 2 cases of myofibromatosis involving multiple bones. Radiology showed lytic lesions in the bone. The proliferation of spindle-shaped myofibroblasts arranged in fascicles with indistinct eosinophilic cytoplasm and bland nuclei, with no pleomorphism and cytological atypia. The characteristic histologic structure was the biphasic nodular growth pattern with cellular and paucicellular regions. The tumors might arrange in a hemangiopericytoma-like pattern. The stroma varied between dense fibrosis and myxoid changes. The reactive new bone formation and inflammatory cell infiltration also existed. Immunohistochemical study showed that the SMA was positive. The surgical resections were performed. One of the patients had tumor recurrence as a result of 11-month follow-up. Conclusions: The pediatric myofibroma/myofibromatosis of the soft tissue and bone is a very rare benign tumor and has a good prognosis. It has a characteristic morphology and its differential diagnosis from other spindle cell tumors could be made with the immunohistochemical analysis.

[Primary intraosseous Rosai-Dorfman disease: a clinicopathological analysis of fourteen cases]

Objective: To investigate the clinicopathological characteristics, histogenesis, immunophenotypes and molecular genetic features of primary intraosseous Rosai-Dorfman disease (RDD) for improving diagnostic accuracy and differential diagnosis. Methods: This retrospective study included 14 RDD cases diagnosed from January 2009 to January 2019 at Beijing Jishuitan Hospital, China. The immunohistochemical staining for S-100, cyclin D1, CD1a and CD207 expression was analyzed. The BRAF V600E and KRAS mutation analyses were performed using the Scorpions amplification refractory mutation system (ARMS) fluorescence quantitative PCR. Results: There were 6 female and 8 male patients, aged from 2 to 64 years (mean 31.4 years). All of the 14 cases occurred in the bone without lymph node disease, while one patient developed additional lesions within vertebra and nasal cavity. Radiographically, the lesions were lytic with sclerotic margins. Histologically, the lesions percolated through the medullary cavity in an infiltrative fashion and alternating hyper- and hypo-cellular regions of histiocytic clusters (seen as alternating dark and light zones at low magnification). Large histiocytes also showed emperipolesis. Some cases had areas of fibrosis and dense lymphoplasmacytic infiltrates. There were vasculitis and an increased number of plasma cells in the cases involving multiple sites. One case showed concurrence of RDD and Langerhans cell histiocytosis(LCH) with inconspicuous increase of Langerhans histiocytes. Immunohistochemical staining showed that the large histiocytes were positive for S-100, CD68 and CD163 in all cases. The nuclear immunoreactivity for cyclin D1 was observed in 13 of the 14 cases. S-100, CD1a and CD207 were positive in the case with concurrence of RDD and LCH. ARMS-PCR results showed that BRAF V600E mutation was observed in the cases with concurrence of RDD and LCH, while there were no KRAS mutations (7/7). Follow-up information was available for 12 patients and ranged from 9 to 49 months. Three of the 12 patients experienced recurrences after the first surgery. Conclusions: Primary intraosseous RDD is rare, and its concurrence with LCH is a very rare phenomenon. Its clinical symptoms, imaging, and pathological manifestations need to be distinguished from other bone lesions. The molecular detection of BRAF V600E and the nuclear expression of cyclin D1 mutations can be used for the diagnosis and differential diagnosis of RDD.

[Role of histological evaluation of periprosthetic tissue in diagnosis of periprosthetic joint infection]

Objective: To evaluate the role of histologicalpathology in the diagnosis of periprosthetic joint infection. Methods: A total of 145 cases of joint arthroplasty during October 2017 and October 2018 from Beijing Jishuitan Hospital were collected. There were 23 cases of infection, including knee joint arthroplasty (12 cases) and hip arthroplasty (11 cases). There were 17 females and 6 males. Patients' age ranged from 39 to 76 years (mean 63 years). The infection was diagnosed if there were >5 neutrophils per high power field in at least 5 high power field. The permanent sections were examined twice separately by two pathologists, and the interval time of histologic examination was at least two weeks. Sensitivity (SE), specificity (SP), positive predictivevalue (PPV), and negative predictive value (NPV) were calculated. The consistency evaluation of histologic examination of two pathologists was calculated by Kappa analysis. Results: The neutrophil cells could locate scattered or focally in the synovium tissue of periprosthetic joint infection. Somewhere, the infiltration of vessel and the perivascular distribution could also exist. Opportunity coincidence rate between two pathologists was 91.3% (Kappa=0.817). The results showed that SE was 60.9%, SP was 100.0%, NPV was 93.1%, PPV was 100.0%. Conclusions: The presence of polymorphonuclear cells in histologic examination is correlated with infection. There was high consistency between histologic examination and clinical diagnosis of joint arthroplasty.

[Synchronous multicentric osteosarcoma: treatment and prognostic factor analysis]

Objective: To identify the clinical outcome and prognostic factors of synchronous multicentric osteosarcoma (SMOS). Methods: The clinical data of 2 602 conventional osteosarcoma patients admitted to Beijing Jishuitan Hospital from January 1995 to June 2018 were retrospectively analyzed. Finally, 56 (2.1%) cases were confirmed as SMOS according to clinical and imaging database, medical record and pathological results.All epidemiological data of SMOS cases,initial diagnosis time, tumor site, number of lesions, chemotherapy, surgical treatment, alkline phosphatase (AKP),lactate dehydrogenase (LDH) and oncological results were collected in our institution. The Survival rate, comparison of various parameters, univariate analysis and multivariate Cox regression were performed with statistical software. Results: There were 41 males and 15 females enrolled in this research, the median and mean ages were 15 and 18 years (range, 8-50 years) respectively. All of them were multi-site involved, whereas the initial complaints of sites distribution were 32 cases of femur, 13 cases of tibia, 4 cases of humerus, 3 cases of fibula, 2 cases of spine, 1 case of sternum and 1 case of calcaneus. Forty-four of 56 cases performed adjuvant chemotherapy and 31 of them underwent surgical treatment. The mean follow-up time was 15.4 (range, 1-186) months. Thirty-five cases died of disease at the end of the follow-up. The 5-year survival rate was 10.4%. According to the number of lesions stratification, the 2-year survival rates in patients with low (<5 sites) and high (≥5 sites) tumor load was 33.6% and 0, respectively (χ(2)=6.697, P=0.010). The 2-year survival rate of chemotherapy and non-chemotherapy patients was 20.8% and 0, respectively (χ(2)=6.998, P=0.008), the value of AKP after chemotherapy(median: 272 IU/L) significantly decreased when compared with that at the initial diagnosis (median: 454 U/L) (Z=-3.274, P=0.001).The 2-year survival rate in patients with and without standard chemotherapy was 55.6% and 0, respectively (χ(2)=8.798, P=0.003). The 2-year survival rate was 25.0% in the surgical group and 0 in the non-surgical group, respectively (χ(2)=7.942, P=0.005). Multivariate cox regression analysis with the forward Wald method indicated that standard chemotherapy was the only variable contributor to survival and prognosis of multifocal osteosarcoma. Conclusions: SMOS has low survival rate and poor prognosis. Chemotherapy and surgery can improve the survival rate, standard chemotherapy is an independent prognostic factor.

[Clinicopathological and ALVAL score analysis of pseudotumor-like tissue around aseptic joint arthroplasty]

Objective: To analyze the clinicopathological features of pseudotumor-like tissue around aseptic joint arthroplasty and aseptic lymphocytic vasculitis-associated lesions (ALVAL) scores. The characters of wear granules were observed. Methods: Total 122 cases were retrieved from the surgical pathology files between May 2015 and August 2018 in the department of pathology in Beijing Jishuitan Hospital, which included the knee joint arthroplasty (10 cases) and hip arthroplasty (112 cases). There were 62 females and 60 males. Patients' age ranged from 29 to 86 years (mean 56 years). The pseudotumor-like tissue around aseptic joint arthroplasty were stained with HE and analyzed by two ALVAL score systems. The characters of wear granules were observed by light microscope and polarized light. Results: The cohort included 62 females and 60 males. Patients' age ranged from 29 to 86 years (mean 56 years). Compbell-ALVAL system includes synovial lining,inflammatory infiltrate and tissue organization. The scores were: low (0-4): 18cases; moderate (5-8): 101 cases; high (9-10): 3 cases. Oxford-ALVAL system only evaluated the inflammatory infiltrate,and the scores were:0 grade:56 cases; 1 grade:51 cases; 2 grade: 12 cases; 3 grade:3 cases. Cases with high score in the Compbell-ALVAL system were concordant with the 3 grade of the Oxford-ALVAL system. Under light microscope,the metal particles were small black granules; the polyethylene fibers were needle-like and easily visible in polarized light. The polymethylmethacrylate showed clear spaces because of particle melting. Conclusions: The Compbell-ALVAL scoring system is based on the histologic analysis of pseudotumor-like tissue around aseptic joint arthroplasty, and the Oxford-ALVAL scoring systems is based on lymphocytic response. The wear particles could be differentiated by the features in the light microscope.

[Clinical, radiologic and pathologic features of giant cell tumor of bone treated with denosumab]

Objective: To investigate the radiological and histopathological features of giant cell tumor of bone treated with RANKL inhibitor denosumab. Methods: Eleven cases were retrieved from the surgical pathology records between March 2015 and June 2017 in Beijing Jishuitan Hospital. Formalin fixed, paraffin embedded specimens were collected and the histological features were evaluated. The imaging features including X ray, magnetic resonance imaging, and computed tomography were also reviewed. Results: These 11 cases of giant cell tumor of bone were derived from five female and six male patients, with age ranged from 20 to 62 years (mean age, 35 years). The tumors were located in the sacrum (6 cases), femur (2 cases), radius (1 case), tibia (1 case) and patella (1 case), respectively. Histologically, all cases showed depletion of giant cells, proliferation of mononuclear cells and different degrees of ossification 3 to 6 months after denosumab therapy. Radiography showed marked osteosclerosis and sclerotic rim formation. Three cases of the sacrum recurred after 5, 6 and 11 months of surgery, and the remaining cases showed no recurrence within follow-up of 1 to 14 months. Conclusions: Denosumab treated giant cell tumors morphologically differ from untreated tumors. Careful attention to a history of denosumab administration is crucial to avoid misdiagnosis and to allow proper differentiation from other tumors and tumor-like lesions.

[Dedifferentiated chordoma of sacrococcygeal region: a clinicopathologic analysis and review of literature]

Objective: To study the clinicopathologic features of dedifferentiated chordoma. Methods: Four cases of dedifferentiated chordoma of sacrococcygeal region were collected at Beijing Jishuitan Hospital, from 2009 to 2014. HE and immunohistochemistry (EnVision method) were used to observe the clinical, radiological and histological features of dedifferentiated chordoma and to make the diagnosis and differential diagnosis. The literature was reviewed. Results: Four cases of dedifferentiated chordoma were all located in the sacrococcygeal region. The mean age at diagnosis was 57 years (range 49-64 years). There were 1 female and 3 males. Histologically, there were two components of conventional chordoma and dedifferentiated sarcoma with or without transitional area between them. The histology of dedifferentiated components includes undifferentiated sarcoma and fibrosarcoma. Immunohistochemical study showed that cytokeratin, epithelial membrane antigen, S-100, Brachyury were positive in the portion of chordoma while p53 were positive in the portion of undifferentiated sarcoma. INI1 and vimentin were both positive. Conclusions: The dedifferentiated chordoma is very rare. The diagnosis should combine the histological characters and immunohistochemical results and should be differentiated from the sarcomatoid chordoma, poorly differentiated chordoma and other high grade sarcoma. p53 may play a role in the malignant transformation mechanism of chordoma.