Analysis of clinical and pathological characteristics of retroperitoneal paraganglioma and associated prognostic factors.

BACKGROUND AND OBJECTIVES: The aim of this study is to explore the long-term prognostic risk factors associated with patients diagnosed with retroperitoneal paraganglioma (RPGL) and examine their clinical and pathological characteristics. METHODS: Expressions of biomarkers were identified using immunohistochemistry (IHC) and case databases were retrospectively searched. Survival analysis was performed using Kaplan-Meier and Cox risk regression to identify the factors that influence the postoperative progression-free survival of patients with RPGL. RESULTS: A total of 105 patients, most of whom had tumors situated in the paraaortic region, and whose average tumor size was 8.6 cm, were enrolled in this study. The average follow-up duration was 51 months, with a mortality rate of 19% and a recurrence and metastasis rate of 41.9%. Tumors were assessed using the modified Grading system for Adrenal Pheochromocytoma and Paraganglioma (GAPP), and SDHB, S-100, and Ki-67 were stained using IHC in all cases. Out of the total cases examined, negative in SDHB expression were observed in 18.1% of cases, S-100 expression was negative in 36.2% of cases, and endovascular tumor enboluswas present in approximately 25.7% of cases. The results of the univariate analysis indicated that several factors significantly influenced the progression-free survival of patients with PGL as follow: maximum tumor diameter (>5.5 cm), tumor morphological features, tumor grading (modified GAPP score > 6), SDHB negative, S-100 negative, and expression of proliferation index Ki-67 (>3%) (X2 = 4.217-27.420, p < 0.05). The results of the multivariate analysis indicated that negative of S-100 (p = 0.021) and SDHB (p = 0.038), as well as intravascular tumor thrombus (p = 0.047) expression were independent risk factors for progression-free survival in patients. CONCLUSION: RPGL is characterized by diverse biological features and an elevated susceptibility to both recurrence and metastasis. Both SDHB and S-100 can be employed as traditional IHC indicators to predict the metastatic risk of PGL, whereas the tumor histomorphology-endovascular tumor enbolus assists in determining the metastasis risk of RPGL.

[TFE3-rearranged perivascular epithelioid cell tumors: a clinicopathological analysis of eight cases].

Objective: To investigate the clinicopathological, immunohistochemical and molecular genetic characteristics of TFE3-rearranged perivascular epithelioid cell tumor (PEComa). Methods: Eight cases of PEComa with TFE3 rearrangement diagnosed in the First Affiliated Hospital of Air Force Medical University from January 2014 to July 2022 were collected. Three were consultation cases and 5 were collected from our hospital; 7 cases were resection specimens and 1 case was a needle biopsy specimen. Routine histolopathological analysis, immunohistochemical staining, fluorescence in situ hybridization (FISH) and the next-generation sequencing were performed. Clinical data were collected and the prognosis was assessed. Results: The 8 patients consisted of 5 females and 3 males with a median age of 45 years (ranged from 25 to 65 years). The tumor location included 1 uterus, 1 liver, 1 urachus, 2 kidneys, 1 abdominal cavity, 1 colon, and 1 retroperitoneum (3 subsequent recurrences in the abdominal cavity, pelvis and ovary, and abdominal cavity, respectively). Morphologically, the tumor cells were uniform and epithelioid with translucent or eosinophilic cytoplasm. They were arranged in nests or sheets, most of which were separated by thin-walled blood vessels. There were no papillary structures, and no overt smooth muscle or fat components. Atypical features were seen in 3 cases, with bizarre nuclei and tumor giant cells. Large areas of necrosis were visible, and mitosis was common (up to 28/50 HPF). Melanin deposition was present in 3 cases. Immunohistochemical staining showed diffuse and strong positivity for TFE3 in 8/8 cases and for HMB45 in 6/8 cases; focal positivity for Cathepsin K and Melan-A in 6/8 cases and for SMA in 2/8 of cases. All cases were negative for CKpan, PAX8 and Desmin. TFE3 gene break-apart was detected by FISH in all 8 cases, 4 of which underwent next-generation sequencing, and it revealed that 2 cases presented with SFPQ::TFE3 fusion, 1 case with ASPSCR1::TFE3 fusion, and 1 case with no chimeric fusion. Seven cases were followed up for 4-94 months. All cases were alive; 4 cases were disease-free, 2 cases showed recurrence, and 1 case had metastasis at initial diagnosis. Conclusions: TFE3-rearranged PEComa has unique histomorphological, immunohistochemical and molecular characteristics. The biological behavior is aggressive, which could lead to recurrence and metastasis, and warrants close clinical follow-up.

Expression and function of Siglec-15 in RLPS and its correlation with PD-L1: Bioinformatics Analysis and Clinicopathological Evidence.

Purpose: Retroperitoneal liposarcoma (RLPS) is a rare malignancy without effective treatment. Since current treatment for unresectable RLPS is unsatisfactory, immunotherapy and targeted therapy are urgently needed. Siglec-15 is a transmembrane protein highly homologous to PD-L1 and is involved in tumor immune escape. The biological function of Siglec-15 in RLPS, its prognostic relevance and its relationship with PD-L1 need to be further clarified. In this study, we aimed to explore the biological function of Siglec-15 in sarcomas through bioinformatics analysis, and we also evaluated Siglec-15 and PD-L1 expression in RLPS samples. The relationship between the expression of Siglec-15 and PD-L1 and their clinicopathological relevance and prognostic value were also investigated in clinical RLPS patients. Methods: The RNA sequencing data of 259 sarcoma cases and 48 RLPS cases from TCGA were used to analyze the Siglec-15 expression and the differentially expressed genes (DEG) related with Siglec-15 expression. In addition, DEGs were subsequently analyzed through the gene ontology (GO)/ Kyoto Encyclopedia of Genes and Genomes (KEGG) and protein-protein interaction (PPI) network. Tumor specimens were obtained from 91 RLPS patients of our sarcoma center, and Siglec-15 and PD-L1 expression were evaluated using immunohistochemistry. The correlation between the expression level of these two markers as well as their correlation with clinicopathological factors and prognosis of RLPS patients was also assessed. Results: GEPIA analysis showed that the high expression of Siglec-15 was associated with poor sarcoma OS (P=0.034). A total of 682 differential genes were identified between the high and low expression groups of Siglec-15 in RLPS. Enrichment analysis of the KEGG pathway showed that Siglec-15 was related to the Hippo signaling pathway and the neuroactive ligand-receptor interaction. GO annotation analysis showed that the expression of Siglec-15 may thus be able to affect serine hydrolase activity, alongside signal receptor activator activity. The top 5 genes with the largest number of connection points are APOA1, F2, AHSG, AMBP, SERPINC1. In subsequent studies, we used 91 liposarcoma samples from our center for verification. Siglec-15 was expressed in 84.6% of RLPS cases, whereas PD-L1 was expressed in 17.6% of RLPS cases. A negative correlation was observed between Siglec-15 and PD-L1 expression (P=0.020). In this group of RLPS patients, high Siglec-15 expression was correlated with poorer disease-free survival (DFS) (P=0.021), and it was an independent predictor of DFS (hazard ratio: 2.298; 95% confidence interval: 1.154-4.576; P=0.018). However, we did not find a correlation between PD-L1 expression and overall survival or DFS in RLPS patients. Conclusion: The DEG and signaling pathways identified in the study could provide a preliminary understanding of the underlying molecular mechanisms of Siglec-15 in the development and progression of RLPS. High expression of Siglec-15 was a negative independent predictive factor for DFS of RLPS. The negative relationship between Siglec-15 and PD-L1 expression suggested that the Siglec-15 pathway might be an important supplement to PD-L1 treatment.

Clinicopathologic Features of Retroperitoneal Malignant Solitary Fibrous Tumors.

We aimed to explore the clinicopathologic and histologic characteristics, as well as the (differential) diagnosis of retroperitoneal malignant solitary fibrous tumors (RMSFTs) in this study. Nine cases of RMSFTs were recruited and identified by an experienced pathologist from the Pathology Department of Beijing Shijitan Hospital. Clinical information was extracted from medical records and obtained by phone calls. A systematic review of published literature on RMSFTs was conducted using PubMed. A pre-specified search strategy was adopted using the key words "solitary fibrous tumor" and "retroperitoneum." Case reports and literature published in the China Academic Journals (CNKI) and WAN FANG databases were also included. In total, 58 patients (33 males and 25 females) were included; their age ranged from 17 to 83 years, with a median age of 52 years. The tumor size ranged from 4 to 36 cm, and most patients had abdominal masses and pain. Of these patients, 56 underwent surgical resection, and two patients died and underwent an autopsy. All patients were followed up for up to 288 months (with a median follow-up of 36 months). RMSFTs are extremely rare. Their diagnosis mainly relies on the histological morphology and the expression profiles of a panel of pathologic molecules measured by immunohistochemistry. Diagnosis of RMSFTs is usually based on the expression of biomarkers such as vimentin, CD34, Bcl-2, CD99, and STAT6. Differential diagnosis includes spindle-shaped cell tumors, such as schwannoma, gastrointestinal stromal tumors, dermatofibrosarcoma protuberans, synovial sarcoma, malignant peripheral nerve sheath tumors, and fibrosarcoma. RMSFTs are prone to recur and even metastasize. Complete resection remains a major treatment, and close follow-up is highly recommended.

High Expression of microRNA-371a-3p in Cystic Fluid of Post-Chemotherapy Teratoma with Concurrent Normal Serum Levels in Patients with Non-Seminomatous Testicular Germ Cell Tumours.

BACKGROUND: MicroRNA-371a-3p (miR-371), the novel serum biomarker of testicular germ cell tumours (GCTs), is produced by undifferentiated subtypes of GCTs but not by teratoma. Cystic teratoma developing from retroperitoneal metastases of GCT subsequent to chemotherapy had been shown to contain high levels of classical serum tumour markers of GCT in the presence of normal marker levels in serum. To date, no information is available regarding the presence of miR-371 in the cystic fluid of residual teratoma after chemotherapy. METHODS: Four patients (age 18-26 years) undergoing retroperitoneal lymph node dissection (RPLND) for cystic residual masses resulting from chemotherapy of bulky retroperitoneal GCT had measurements of miR-371 in both serum and cystic fluid aspirated from surgical specimens. Measurement of the miR was performed with quantitative real-time PCR using miR-30b-5p as reference. Results were tabulated and analysed in a descriptive manner. RESULTS: Histologically, all of the surgical specimens involved teratoma only with no evidence of vital undifferentiated GCT tissue. All patients were cured. Prior to RPLND, miR-371 serum levels were not measurable or close to zero in all of the patients. Cystic fluid revealed elevated levels of miR-371 in 3 patients and traces of miR in one. CONCLUSIONS: The detection of miR-371 in the cystic fluid of teratoma is somewhat enigmatic since this GCT subtype usually does not express the miR. Two hypotheses may explain the finding: First, miR-371 molecules were released into the cystic fluid by active GCT tissue prior to chemotherapy. High levels were kept after regression of vital GCT tissue because the cystic lumen is without a specific drainage system. Second, teratoma cells lining the interior cyst wall may shed small amounts of miR-371 into the lumen. Because of the lacking drainage system, even small levels may accumulate. The present finding adds to the understanding of the biology of the novel biomarker of GCT.

The use of pharmacokinetically guided carboplatin chemotherapy in a pre-term infant with neuroblastoma-associated spinal cord compression.

Neonatal neuroblastoma may require chemotherapy either due to mass effect or unfavourable cytogenetics. This case focuses on using pharmacokinetic (PK) guided chemotherapy to treat neonatal neuroblastoma. A newborn baby was noted to have left leg immobility. Imaging showed a retroperitoneal tumour with spinal canal extension causing spinal cord compression. PK-guided carboplatin was given after conventionally dosed chemotherapy demonstrated no improvement. After initiation of PK therapy, clinical and radiological improvement was seen. We discuss our decision to use PK-guided chemotherapy despite guidelines recommending weight-based dosing and discuss the benefits in terms of clinical efficacy without increased toxicity.

[Prognostic factors analysis of Ki-67, α-SMA expression in retroperitoneal leiomyosarcoma].

Objective: To investigate the expression and prognostic value of alpha smooth muscle actin(α-SMA) and Ki-67 in retroperitoneal leiomyosarcoma. Methods: Fifty retroperitoneal leiomyosarcoma patients who underwent operation in Chinese People's Liberation Army General Hospital from May 2002 to December 2015 were retrospectively analyzed. There were 14 males and 36 females form 21 to 79 and an average age of 48. Kaplan-Meier estimations and Cox regression analyses were performed. Results: Of the 50 cases, 45 patients underwent complete resection, and others are not. The overall 1, 3, 5-year survival rates were 86.0%, 46.0% and 28.0%, respectively. Tumor size, extent of resection, pathological stage, and expression levels of Ki-67 and alpha smooth muscle actin (α-SMA) were closely related to the survival of retroperitoneal leiomyosarcoma patients (all P<0.05), respectively. Multivariate analysis showed that pathological grade and degree of surgical resection were independent risk factors in the prognosis of patients (P<0.05). Conclusion: The high expression of α-SMA and Ki-67 are indicators of poor prognosis in retroperitoneal leiomyosarcoma, which can be used as a potential survival predictor in patients with retroperitoneal leiomyosarcoma.

[Recurrence of a Giant Retroperitoneal Leiomyosarcoma Six Years after the Initial Surgery].

A 51-year-old man came to our department because of a large abdominal mass. CT, MRI, and sonography revealed a large tumor adjacent to the retroperitoneal area. A resection was performed, and histologically we confirmed the diagnosis as a leiomyosarcoma originating from the retroperitoneum. Six years after the initial surgery, the patient came to our outpatient department with a complaint of nausea. A relatively large tumor was seen on a CT scan that was causing obstruction of the duodenum. Another surgery was performed with the final diagnosis as a recurrence of the leiomyosarcoma. After 3 courses of adjuvant chemotherapy with eribulin, the patient presented with abdominal distension. CT revealed a very large tumor with massive invasion to the ileum and colon. This time, we considered the tumor unresectable, and administered chemotherapy with a combination of doxorubicin and ifosfamide. However, after 1 course, the patient's condition worsened and he died of the disease 3 months after the chemotherapy.

E-Cadherin fragments as potential mediators for peritoneal metastasis in advanced epithelial ovarian cancer.

BACKGROUND: Peritoneal dissemination and retroperitoneal lymph node involvement are main routes for tumour spread of epithelial ovarian cancer (EOC), possibly determined by the intercellular connecting protein E-Cadherin (E-Cad) and its fragments. METHODS: Tumour tissue of 105 advanced EOC patients was evaluated for protein expression of E-Cad, ß-Catenin and Calpain by western blotting and immunohistochemistry. Expression patterns were compared between tumours with solely intraperitoneal (pT3c, pN0; n=41) and tumours with retroperitoneal metastases (pT1a-3c, pN1; n=64). Lysates of the EOC cell line SKOV3 and tumour tissue from the intraperitoneal group were tested for E-Cad expression following Calpain treatment. RESULTS: E-Cad full-length (E-Cad-FL, 120 kDa) and two major fragments at 85 kDa (E-Cad-85) and 23 kDa (E-Cad-23) were detected by western blotting. E-Cad-85 expression was significantly higher in tumours with solely intraperitoneal metastases and correlated strongly with E-Cad-23 and the protease Calpain. Calpain-mediated cleavage was identified as a potential mechanism to generate E-Cad-85 from E-Cad-FL by treating lysates from SKOV3 cells and tumour tissue with this enzyme. Increased cytoplasmic localisation of ß-Catenin in tumours with high E-Cad-85 expression corroborates that E-Cad-85 loses the binding site for ß-Catenin after fragmentation, enabling tumour cluster formation and peritoneal dissemination. CONCLUSIONS: Calpain-mediated E-Cad fragmentation appears to promote intraperitoneal EOC progression. Understanding these mechanisms might eventually lead to new tailored subtype-specific diagnostic and therapeutic interventions.

Extended resection including adjacent organs and Ki-67 labeling index are prognostic factors in patients with retroperitoneal soft tissue sarcomas.

BACKGROUND: Because retroperitoneal soft tissue sarcomas (RPS) are extremely rare, there is a significant lack of clinicopathologic information to optimize the treatment strategy. The aim of this study was to evaluate the prognostic factors in RPS, with particular focus on the Ki-67 labeling index (LI). METHODS: We included the data from a total of 23 patients who received treatment for primary RPS at a single center. The variables analyzed in this study included tumor size, histological type, malignancy grade, necrosis, mitosis, and Ki-67 LI. Kaplan-Meier and Cox proportional regression analyses of overall survival (OS) were performed to identify significant prognostic variables. RESULTS: Of the 23 patients who underwent surgical resection, 9 (39%) underwent simple resection of the tumor and 14 (61%) extended resection including the adjacent organs. In the univariate analysis, a simple tumor resection and a high Ki-67 LI were associated with shorter OS. The multivariate analysis revealed that simple tumor resection and a high Ki-67 LI were independent negative prognostic factors for OS. CONCLUSIONS: Our results suggested that combined resection of RPS and its adjacent organs improved OS. Pathologically, a high Ki-67 LI was significantly associated with negative prognosis.

JUN oncogene amplification and overexpression block adipocytic differentiation in highly aggressive sarcomas.

The human oncogene JUN encodes a component of the AP-1 complex and is consequently involved in a wide range of pivotal cellular processes, including cell proliferation, transformation, and apoptosis. Nevertheless, despite extensive analyses of its functions, it has never been directly involved in a human cancer. We demonstrate here that it is highly amplified and overexpressed in undifferentiated and aggressive human sarcomas, which are blocked at an early step of adipocyte differentiation. We confirm by cellular and xenograft mouse models recapitulating these sarcoma genetics that the failure to differentiate is dependent upon JUN amplification/overexpression.

Perivascular epitheloid cell tumor (PEComa) mimicking retroperitoneal liposarcoma.

PEComas are a collection of generally rare tumors, defined by the World Health Organization as 'mesenchymal tumors composed of histologically and immunohistochemically distinctive perivascular epitheloid cells'. We describe the case of retroperitoneal PEComa with a liposarcoma-like appearance on cross-sectional imaging, but distinctive immunohistochemistry revealing the correct diagnosis.

[Expression of CD133 in primary retroperitoneal leiomyosarcoma and its relationship with Ki-67].

OBJECTIVE: To explore the correlation between CD133 and proliferative marker Ki-67 in primary retroperitoneal leiomyosarcoma and evaluate their prognostic values. METHODS: A total of 50 primary retroperitoneal leiomyosarcoma samples were collected at our hospital from January 2000 to December 2012. There were 9 males and 41 females. All samples were analyzed for CD133 and Ki-67 protein expression by PV6000 immunohistochemistry. Their median age was 49 (27-75) years. All cases were successfully followed up. RESULTS: CD133 expression was detected in 74.00% (37/50) of primary retroperitoneal leiomyosarcoma samples. The CD133-positive rates of histological grades I & II primary leiomyosarcoma were 7/13 and 76.70% (23/30) respectively. All grade III samples (n = 7) were CD133 positive. And the expression of CD133 had a positive correlation with tumor size, mitotic counts and histological grade (χ(2) = 4.925, 4.525, 10.080; P = 0.026, 0.033, 0.013). The survival time of CD133-positive patients with M (Q1, Q3) was 32 (17, 56) months versus 44 (26, 65) months for those negative ones. The expression of Ki-67 was detected in 84.00% (42/50) of primary retroperitoneal leiomyosarcoma samples and its expression showed a positive correlation with mitotic counts. The expressions of CD133 and Ki-67 were positively correlated in primary retroperitoneal leiomyosarcomas (P = 0.009). Log-rank test showed that positive expressions of CD133 and Ki-67 and 5-year patient survival rate were correlated (P = 0.021, 0.049). Multivariate analysis showed that CD133 and mitotic counts were independent prognostic indicators for primary retroperitoneal leiomyosarcomas (HR = 2.040, 2.422; P = 0.000, 0.018). CONCLUSIONS: CD133 plays an important role in the progression of primary retroperitoneal leiomyosarcomas so that it may be used as a marker for patient prognosis. Combined detection of CD133 and Ki-67 has a prognostic value in patients with primary retroperitoneal leiomyosarcoma.

[Extrarenal malignant rhabdoid tumor of childhood: a clinicopathologic analysis of 8 cases].

OBJECTIVE: To study the clinicopathologic characteristics of extrarenal malignant rhabdoid tumor (E-MRT) with emphasis on diagnosis and differential diagnosis. METHODS: The clinical and pathologic data of 8 E-MRT cases were reviewed. The outcome was analyzed. RESULTS: There were four males and four females. The age at presentation ranged from 3 days to 8 years (mean, 2.6 years; median, 3 years). The tumors were located in the extremities (n = 1), head and neck (n = 2), trunk (n = 2), cervical cord (n = 1), liver (n = 1) and retroperitoneum (n = 1). Histologically, the tumors were composed of a diffuse proliferation of rounded or polygonal cells with eccentric nuclei, prominent nucleoli, and glassy eosinophilic cytoplasm containing hyaline-like inclusion bodies, arranged in sheets and nests. Cellular atypia was easily observed and mitotic activity was high. Necrotic and hemorrhagic areas were abundant. On immunohistochemistry, the tumor cells expressed vimentin and epithelial marker such as EMA, AE1/AE3, and CAM5.2. The absence of INI1 protein expression was a distinctive feature. Follow-up of all eight cases revealed five deaths in one year and the other three were disease-free at last follow-up of one month, three months and seven months. CONCLUSIONS: E-MRT is a rare and highly aggressive tumor of infancy and childhood. Recurrence and distant metastasis was common and the 5-year survival rate is low. Increased awareness of the clinocopathologic features and immunophenotypes of E-MRT is helpful for correct diagnosis and effective treatment.

Multi-omics joint analysis revealed the metabolic profile of retroperitoneal liposarcoma.

Retroperitoneal liposarcoma (RLPS) is the main subtype of retroperitoneal soft sarcoma (RSTS) and has a poor prognosis and few treatment options, except for surgery. The proteomic and metabolic profiles of RLPS have remained unclear. The aim of our study was to reveal the metabolic profile of RLPS. Here, we performed proteomic analysis (n = 10), metabolomic analysis (n = 51), and lipidomic analysis (n = 50) of retroperitoneal dedifferentiated liposarcoma (RDDLPS) and retroperitoneal well-differentiated liposarcoma (RWDLPS) tissue and paired adjacent adipose tissue obtained during surgery. Data analysis mainly revealed that glycolysis, purine metabolism, pyrimidine metabolism and phospholipid formation were upregulated in both RDDLPS and RWDLPS tissue compared with the adjacent adipose tissue, whereas the tricarboxylic acid (TCA) cycle, lipid absorption and synthesis, fatty acid degradation and biosynthesis, as well as glycine, serine, and threonine metabolism were downregulated. Of particular importance, the glycolytic inhibitor 2-deoxy-D-glucose and pentose phosphate pathway (PPP) inhibitor RRX-001 significantly promoted the antitumor effects of the MDM2 inhibitor RG7112 and CDK4 inhibitor abemaciclib. Our study not only describes the metabolic profiles of RDDLPS and RWDLPS, but also offers potential therapeutic targets and strategies for RLPS.

The association between CD34 expression status and the clinicopathological behavior of dedifferentiated liposarcoma.

Lipogenic and fibrous tumors are thought to originate from CD34-positive stromal fibroblastic/fibrocystic cells. Well-differentiated lipogenic tumors typically express CD34, whereas dedifferentiated liposarcoma (DDLPS) often loses it. We conducted survival analyses involving 59 patients with DDLPS. Males comprised 53% of the cohort, and the median age at the time of wide resection of primary DDLPS was 60 years. Loss of CD34 expression was defined as when ≥50% of the dedifferentiated area was immunohistochemically negative for CD34. As a result, 39 of the 59 patients showed loss of CD34 expression during the initial operation for DDLPS. In the univariate analyses, the tumor site in the retroperitoneum/abdominal cavity and loss of CD34 expression were significantly associated with poor overall survival. In the multivariate analyses, loss of CD34 expression (HR = 2.26; 95% CI = 1.02-5.02; p = 0.04) and the tumor site in the retroperitoneum/abdominal cavity (HR = 3.11; 95% CI = 1.09-8.86; p = 0.03) were retained as independent prognostic factors. Six CD34-positive cases lost CD34 expression when they developed metastasis and/or local recurrence, suggesting that the loss was associated with the later stage of the tumor. Therefore, an association existed between the loss of CD34 expression and clinicopathological behaviors such as poorer prognoses and recurrence.

Prevalence of MED12 mutations in uterine and extrauterine smooth muscle tumours.

AIMS: To determine the prevalence of MED12 mutations in smooth muscle tumours of different organs. METHODS AND RESULTS: A total of 142 smooth muscle tumours of the uterus, gastrointestinal tract, retroperitoneum and soft tissue were analysed for MED12 mutations using Sanger sequencing. Among the uterine tumours that were examined, MED12 mutations were identified in 36 of 45 conventional leiomyomas (80%), two of six cellular leiomyomas (33%), one of four bizarre leiomyomas (25%), none of four lipoleiomyomas (0%), and two of 12 leiomyosarcomas (17%). The two MED12-mutated leiomyosarcomas were associated with benign leiomyomatous components that also harboured MED12 mutations identical to those in the respective leiomyosarcomatous components. None of the extrauterine smooth muscle tumours, including the leiomyomas, leiomyosarcomas, and angioleiomyomas, had MED12 mutations. CONCLUSIONS: Among uterine smooth muscle tumours, MED12 mutations are frequently present in conventional leiomyomas, but are significantly less common in histological variants of leiomyoma and leiomyosarcoma. In contrast to uterine lesions, none of the extrauterine smooth muscle tumours had MED12 mutations.

Primary retroperitoneal mucinous cystadenoma with a sarcoma-like mural nodule: an immunohistochemical study with histogenetic considerations and literature review.

Primary retroperitoneal mucinous cystadenomas (PRMCs) are extremely rare tumors and their association with sarcoma-like mural nodules (SLMNs) has not been described thoroughly. The aim of this study is to characterize the gross and microscopic features and the immunohistochemical profile of the first case of PRMC with SLMN and to discuss the differential diagnosis of SLMNs. The literature related to primary retroperitoneal mucinous tumors is reviewed in an attempt to clarify the histogenesis of the epithelial and sarcomatoid components of the associated mural nodules. A 34-yr-old woman presented with a 14-cm retroperitoneal cystic lesion with a 6-cm mural nodule. An immunohistochemical study with a panel of 19 antibodies and a histochemical study for mucin stains were performed. The epithelial component of the PRMC showed positive staining for cytokeratin (CK) 7, CK AE1/3, epithelial membrane antigen, carcinoembryonic antigen, and calretinin. The neoplasm was not immunoreactive for CK 20, CK 5/6, and the other antibodies used in this study. In addition, it stained positively for mucin by mucicarmine, periodic acid-Schiff, and Alcian blue. The stromal cells of the cyst showed estrogen receptor positivity. SLMN cells were negative for all CKs and other epithelial markers used in the study, but they showed diffuse positive staining for vimentin and CD68, and positive staining for Ki-67 was demonstrated in 25% of these cells. The immunohistochemical and histochemical profiles of PRMC were similar to those of ovarian mucinous neoplasms and the mesothelium. The formation of SLMNs seems to be related to subepithelial hemorrhage and some reactive epithelial changes near the mural nodules. The specific immunohistochemical and morphologic features of SLMNs are helpful in differentiating them from malignant mural nodules, including true sarcomas, osteoclast-rich undifferentiated carcinomas, and carcinosarcomas. Such a differentiation is critical in view of its significant impact on the management of these neoplasms, particularly in young patients who desire to preserve their fertility.

Non-functioning adrenocortical carcinoma arising in an adrenal rest: immunohistochemical study of an adult patient.

Adrenal rest is uncommon in adults, and usually represents a small lesion incidentally detected during surgery or autopsy. The adrenal rest can be detected anywhere along the path of embryonic migration of adrenal cortex, including celiac axis, genitals and broad ligament, and may be formed with the separation of cortical fragments by the migration of medullary elements from the sympathochromaffin tissue into the preformed cortical primordium. In addition, even primary adrenocortical carcinoma is a rare tumor with incidence 0.5-2 per million annually; therefore, adrenocortical carcinoma arising in adrenal rests is extremely rare. We encountered a patient with non-functioning ectopic adrenocortical carcinoma in retroperitoneum. A 34-year-old female presented with an incidentally discovered retroperitoneal mass revealed by abdominal ultrasound in her regular health examinations. She did not have any clinical abnormalities and underwent hand-assisted laparoscopic resection of the tumor. A dark-brown tumor, measuring 65 × 56 × 45 mm, was identified in the retroperitoneal space between lower pole of right kidney and inferior vena cava. Histologically, the tumor was predominantly composed of compact eosinophilic cells forming nest-like arrangements and diffusely positive for the steroidogenic factor-1. The tumor met four of the criteria of Weiss used in histological diagnosis of adrenocortical carcinoma (eosinophillic cytoplasm, nuclear atypia, atypical mitosis, and sinusoidal invasion). The tumor cells were immunohistochemically positive for 17α-hydroxylase, dehydroepiandrosterone sulfotransferase and 3ß-hydroxysteroid dehydrogenase, each of which is involved in the synthesis of adrenocortical steroids. Therefore, based on these findings, we diagnosed this tumor as ectopic adrenocortical carcinoma arising in adrenal rest of retroperitoneum.