Epithelioid angiosarcoma of the calf: a case report of an atypical imaging appearance.

Angiosarcoma is an uncommon cause of soft tissue malignancy, accounting for approximately 2% of all soft tissue sarcomas. Of these, epithelioid angiosarcoma represents a morphologic subtype, where the malignant endothelial cells demonstrate a predominantly or exclusively epithelioid appearance. Overall, epithelioid angiosarcoma shares similar imaging characteristics to conventional angiosarcoma including a T1 hypointense to isointense and T2 hyperintense mass, which demonstrates avid enhancement, serpentine feeding vessels, and overlying skin thickening on MRI. The case herein describes a case of epithelioid angiosarcoma in a 65-year-old female presenting with an enlarging calf mass and lower extremity pain. Initial imaging features, particularly on MRI, were highly unusual for angiosarcoma which was thus not strongly considered in the initial differential diagnosis. However, once diagnosis of epithelioid angiosarcoma was confirmed following resection, pathologic correlates were utilized to account for the unusual imaging findings retrospectively. The goal of this study is to not only describe an atypical presentation of an uncommon diagnosis but also attempt to rationalize the unexpected imaging findings with gross and microscopic correlates. Further, the utility of radiology-pathology correlation demonstrated in this case may be useful to others when evaluating similar lesions with unexpected MRI characteristics.

Molecular testing for the clinical diagnosis of fibrolamellar carcinoma.

Fibrolamellar carcinoma has a distinctive morphology and immunophenotype, including cytokeratin 7 and CD68 co-expression. Despite the distinct findings, accurate diagnosis of fibrolamellar carcinoma continues to be a challenge. Recently, fibrolamellar carcinomas were found to harbor a characteristic somatic gene fusion, DNAJB1-PRKACA. A break-apart fluorescence in situ hybridization (FISH) assay was designed to detect this fusion event and to examine its diagnostic performance in a large, multicenter, multinational study. Cases initially classified as fibrolamellar carcinoma based on histological features were reviewed from 124 patients. Upon central review, 104 of the 124 cases were classified histologically as typical of fibrolamellar carcinoma, 12 cases as 'possible fibrolamellar carcinoma' and 8 cases as 'unlikely to be fibrolamellar carcinoma'. PRKACA FISH was positive for rearrangement in 102 of 103 (99%) typical fibrolamellar carcinomas, 9 of 12 'possible fibrolamellar carcinomas' and 0 of 8 cases 'unlikely to be fibrolamellar carcinomas'. Within the morphologically typical group of fibrolamellar carcinomas, two tumors with unusual FISH patterns were also identified. Both cases had the fusion gene DNAJB1-PRKACA, but one also had amplification of the fusion gene and one had heterozygous deletion of the normal PRKACA locus. In addition, 88 conventional hepatocellular carcinomas were evaluated with PRKACA FISH and all were negative. These findings demonstrate that FISH for the PRKACA rearrangement is a clinically useful tool to confirm the diagnosis of fibrolamellar carcinoma, with high sensitivity and specificity. A diagnosis of fibrolamellar carcinoma is more accurate when based on morphology plus confirmatory testing than when based on morphology alone.

A Rare Pediatric Example of Subcutaneous Extraskeletal Osteosarcoma: A Case Report and Review of the Morphologic Differential Diagnosis.

Primary extraskeletal osteosarcoma is an exceedingly rare malignant neoplasm that accounts for approximately 1% of soft tissue sarcomas and most often occurs in the deep soft tissues of adults. Extraskeletal osteosarcoma is characterized by the production of osteoid, bone, and/or chondroid matrix. The diagnosis of extraskeletal osteosarcoma requires careful radiologic and clinical correlation to ensure that the patient does not have an underlying bone primary. This is a case report of primary subcutaneous extraskeletal osteosarcoma arising in the thigh of a 15-year-old girl with a complex karyotype, and the morphologic differential diagnosis is reviewed.

Primary Gastric Leiomyosarcoma: A Rare Case.

Gastric leiomyosarcoma is extremely rare. In this paper, we present a case of primary gastric leiomyosarcoma located in the fundus/cardia region. The tumoral spindle cells show diffusely moderate nuclear atypia, with focally marked atypia and rare mitotic figures. Additionally, the tumoral cells exhibit positive immunoreactivity to smooth muscle actin and desmin while testing negative for CD117 (c-kit). The tumor was successfully resected through a laparoscopic partial gastrectomy, and the patient experienced a full recovery. There has been no recurrence or metastatic tumor detection during the seven-year follow-up period. Furthermore, we conducted a literature review on primary gastric leiomyosarcoma.

The Landscape of Primary Gastric Leiomyosarcoma in Texas Population: Analysis of Texas Cancer Registry Data.

Introduction Primary gastric leiomyosarcoma is an extremely rare disease. There have been no previous studies regarding gastric leiomyosarcoma in the Texas population. Methods Anonymous data of gastric leiomyosarcoma from the Texas Cancer Registry (TCR) was used. Information collected included the primary tumor site, age at diagnosis, gender, race/ethnicity, diagnosis and treatments, tumor size, lymph node and metastasis status, grade and stage, body weight and height, public health regions and payer, metropolitan status, neighborhood poverty level, smoking status, survival interval, and cause of death for statistical analysis. Result Thirty-three cases from 2003-2019 were selected. Primary gastric leiomyosarcoma was more commonly diagnosed in patients over 50 years of age, females, and individuals of white race. The diagnosis was primarily based on histology, and the disease was typically treated with surgery and chemotherapy. At the time of diagnosis, 45.5% of patients were in the late stage, and 48.5% of patients died from gastric leiomyosarcoma with a mean survival interval of 15.3 months. BMI scores showed a positive correlation with survival intervals. Surveillance, Epidemiology and End Results (SEER) tumor staging was associated with the prognosis of gastric leiomyosarcoma. Conclusion There were multiple disparities among patients with primary gastric leiomyosarcoma in the Texas population. The SEER summary stage was associated with the prognosis of gastric leiomyosarcoma.

Heterotopic Hepatic Tissue in the Placenta: A Case Report.

Heterotopic hepatic tissue in placenta or umbilical cord is rare. The exact mechanism by which this heterotopia occurs has not been fully understood but is thought to be related to yolk sac primordia. To date, a handful of such cases have been reported. We present a case of heterotopic liver tissue within a chorionic stem villus of a 37 week-growth restricted neonate and describe the tissue morphology and its immunohistochemistry workup.

Solitary Fibrous Tumor of Hard Palate: A Case Report and Literature Review.

Solitary fibrous tumor (SFT) is a mesenchymal tumor accounting for less than 2% of soft tissue tumors and has variable clinical behavior. It can arise in many anatomical locations of the body and in rare occasions in the oral cavity mostly in buccal mucosa and tongue. To date, a handful of such cases have been reported in the hard palate. We present a case of SFT in the hard palate of a 32-year-old man and describe the tissue morphology, immunohistochemistry workup, and follow-up together with literature review.

A Focus of Differentiated Myeloid Sarcoma in a Ligation Specimen of the Fallopian Tube: No Evidence of Hematologic Abnormality in 18 Years of Follow-up Despite Absence of Treatment.

A 0.2-cm intramural focus composed predominantly of myelocytes and metamyelocytes, many CD3+, CD43+ T-lymphocytes, scanty CD20+ B-lymphocytes, rare mast cells, but no eosinophils or myeloblasts was incidentally found in a ligation specimen of the left fallopian tube. The myeloid cells were positive for chloroacetate esterase, myeloperoxidase, myeloid marker BM2, and CD43, and they were negative for CD30, CD34, CD117, ERG, and TDT. The findings in the left fallopian tube were consistent with the diagnosis of differentiated myeloid sarcoma. The right fallopian tube was normal. No hematologic abnormalities were found elsewhere in the body. Curiously, the patient remains free of any hematologic abnormality for 18 years despite absence of treatment.

SMARCB1/INI1-deficient pancreatic undifferentiated rhabdoid carcinoma mimicking solid pseudopapillary neoplasm: A case report and review of the literature.

BACKGROUND: SMARCB1/INI1-deficient pancreatic undifferentiated rhabdoid carcinoma is a very aggressive tumor that is rarely reported in the literature. The tumor has a predominant rhabdoid cell component and different patterns of growth have been reported. CASE SUMMARY: A 59-year-old woman presented with diffuse abdominal pain, increasing in severity and accompanied by weight loss, nausea, and vomiting. Imaging showed a pancreatic head mass. Fine needle aspiration demonstrated atypical epithelioid cells with a pseudopapillary growth pattern suggestive of solid pseudopapillary neoplasm. The excised neoplasm showed monotonous epithelioid and focally spindle cells with pseudopapillary structures, rhabdoid features, and loss of SMARCB1 protein expression with wild-type KRAS, consistent with a SMARCB1/INI1-deficient undifferentiated rhabdoid carcinoma. The patient's condition deteriorated rapidly following surgery and she expired 3 mo post operation. CONCLUSION: In this article, we report the first case of SMARCB1/INI1-deficient undifferentiated pancreatic rhabdoid carcinoma mimicking solid pseudopapillary neoplasm.

Primary bone sarcoma with BCOR internal tandem duplication.

BCOR internal tandem duplications (ITDs) and rearrangements are implicated in the oncogenesis of a subset of undifferentiated sarcomas. To date, BCOR ITD sarcomas have been exclusively found in non-appendicular infantile soft tissues, whereas BCOR-rearranged sarcomas occur in both bones and soft tissues affecting a wider patient age range. Little is known about patient outcome in BCOR ITD sarcomas. We present a BCOR-expressing, primary bone, undifferentiated sarcoma case involving an adolescent male's left tibia that, unexpectedly, harbored a BCOR ITD instead of a BCOR rearrangement. Furthermore, the patient achieved a partial histologic response after receiving a Ewing sarcoma chemotherapy regimen. Our case expands the clinical spectrum of BCOR ITD sarcomas and suggests that childhood and adult BCOR-expressing sarcomas with an undifferentiated histology should be considered for both BCOR rearrangement and ITD screening. Accurate BCOR mutation identification in undifferentiated sarcomas is essential to define their clinical spectrum and to develop effective management strategies.

Does Argininosuccinate Synthase 1 (ASS1) Immunohistochemistry Predict an Increased Risk of Hemorrhage for Hepatocellular Adenomas?

Hepatocellular adenomas (HCAs) often pursue an innocuous clinical course. Recent work has elucidated important subtypes of HCA and biomarkers to identify them, including HCA at an increased risk for malignant transformation. Another key complication of HCAs is the risk of spontaneous tumoral hemorrhage, which may be life-threatening. Identification of a predictive biomarker for this clinical complication would therefore be of clinical value. It has been suggested that Argininosuccinate Synthase 1 (ASS1) immunohistochemistry (IHC) identifies HCA with a high propensity for hemorrhage. The aim of our study was to validate ASS1 IHC as a predictive marker of hemorrhage. Eighty-nine HCAs were collected for ASS1 IHC and subtyped according to published criteria. Clinical records were examined for evidence of tumoral hemorrhage. Twenty-one (23.6%) HCAs were complicated by clinically detected hemorrhage and were more likely to be resected (P=0.0002). Hemorrhage complicated all WHO subtypes of HCA. There was no association between hemorrhage and HCA subtype (P=0.92). Neither the distribution of ASS1 expression nor the intensity of ASS1 expression compared to normal liver showed a significant association with hemorrhage (P=0.051 and 0.34). Interlaboratory comparison of 8 cases showed good agreement regarding the intensity (6/8 and 7/8) and distribution of staining (7/8 and 7/8) across 3 laboratories performing ASS1 IHC. In conclusion, all subtypes of HCA may be complicated by hemorrhage. ASS1 IHC expression did not correlate with hemorrhagic complications. Caution is prudent before routine implementation of ASS1 IHC in clinical practice.

Pleural tuberculosis.

A 35-year-old woman with previously untreated latent tuberculosis was admitted to the hospital for management of a right-sided empyema. After a prolonged hospitalization and several interventions, including chest tubes, bronchoscopy with bronchoalveolar lavage, and a video-assisted thoracoscopic surgery, positive acid-fast bacilli cultures on the initial thoracentesis ultimately led to the diagnosis of pleural tuberculosis. This case highlights the importance of utilizing a combination of diagnostic tests to diagnose pleural tuberculosis, especially in the setting of a negative pleural adenosine deaminase level.

Primary epithelioid angiosarcoma of the temporal bone with initial presentation of otalgia.

Primary angiosarcoma of the bone is exceedingly rare. Here, we report a case of epithelioid angiosarcoma arising from the right temporal bone in a 57-year-old woman who presented with otalgia that was refractory to conventional treatment.

Pedunculated focal nodular hyperplasia in a healthy toddler.

Focal nodular hyperplasia (FNH) is a benign hepatic tumor rarely seen in pediatric patients, with most cases reported in school-aged children with a history of malignancy, liver disease, chemotherapy, or hematopoietic stem cell therapy. Despite having advanced radiographic imaging, diagnosing FNH before surgical resection can be difficult. We report a rare case of pedunculated FNH presenting as a large abdominal mass palpated on physical exam in a healthy 3-year-old girl with no history of malignancy or underlying liver disease. Ultrasound, computed tomography, and magnetic resonance imaging (MRI) did not demonstrate the typical imaging characteristics of FNH, because the mass was pedunculated with a poorly visualized central scar. Because approximately 75% of all primary hepatic tumors in this age group are malignant, this report also discusses the importance of adding hepatobiliary phase imaging with MRI to avoid, if possible, the need for biopsy or surgical resection of a benign hepatic tumor.

Abdominopelvic and Retroperitoneal Low-Grade Fibromyxoid Sarcoma: A Clinicopathologic Study of 13 Cases.

OBJECTIVES: Low-grade fibromyxoid sarcoma (LGFMS) is a rare tumor often arising in the lower extremities. Only rare examples in the abdominal cavity, pelvis, and retroperitoneum have been reported. METHODS: cases of abdominopelvic and retroperitoneal LGFMS were retrieved. MUC4, Actin, ALK, ß-catenin, desmin, DOG1, KIT, S100 protein, and STAT6 testing was performed, and a subset was tested for FUS rearrangement. RESULTS: Sites included intra-abdominal/abdominal wall (four cases), retroperitoneum (three cases), pelvis (three cases), small bowel (two cases), and kidney (one case) (median size, 15 cm; age range, 5-61 years). Tumors harbored spindled cells with mild to moderate atypia, displaying alternating myxoid nodules and hyalinized areas. All cases were positive for MUC4, and five (of five) cases tested harbored FUS rearrangement. Variable positivity for DOG1 (four of 10) and actin (two of 10) was identified. Six tumors recurred, and one patient developed metastasis. CONCLUSION: LGFMS arising in these central locations exhibits similar clinicopathologic features to its counterpart in the extremities. LGFMS at these sites may show limited immunoreactivity for DOG1 and actin.

Superficial Solitary Fibrous Tumor: A Series of 26 Cases.

While superficial (cutaneous/subcutaneous) solitary fibrous tumor (SFT) have been described, definitive diagnosis is difficult due to overlapping features with other tumors. We describe the largest series to date of superficial SFT. For inclusion, SFT had to arise in dermis or subcutis. Twenty-six cases were identified. Patients ranged from 16 to 80 years (mean, 47 y) with a marked female predominance (19 F; 7 M). Tumors involved the head (11), thigh (7), back (3), shoulder (2), upper arm (1), ankle (1), and great toe (1). Mean size was 2.9 cm (range, 1.0 to 7.0 cm). The majority (n=19) had typical histologic features (cellular SFT) with irregular fascicles of spindled cells, staghorn-like blood vessels, and variable amounts of collagen. Necrosis was evident in 3 cases (all <25%). Mitotic activity ranged from 0 to 10 mitotic figures/10 high-power fields (mean, 2 mitotic figures/10 high-power fields). Seventeen of the 18 were positive for STAT6, whereas 21/22 expressed CD34. All were low risk (23/23) by proposed criteria (Demicco and colleagues), including 2 cases with malignant histology. Three could not be risk stratified due to lack of information on tumor size. Follow-up, available on 7 cases, showed no recurrence/metastasis (mean follow-up, 100 mo; range, 2 to 241 mo). Cutaneous SFT are more common in women and most often involve the head. They are usually low risk by proposed criteria and appear to behave in an indolent manner, though larger studies are needed to confirm this. Recognition that SFT may present as a superficial mass will avoid misclassification as other CD34-positive neoplasms that frequently arise in the skin and subcutaneous tissue.

Giant Cell Tumor of Bone in Patients 55 Years and Older: A Study of 34 Patients.

OBJECTIVES: Most giant cell tumors of bone (GCTs) occur in patients aged 20 to 40 years. We analyzed features of GCT in patients 55 years or older. METHODS: GCTs were examined for fibrosis, matrix, cystic change, histiocytes, mitoses, and necrosis. Clinical/radiologic data were collected. RESULTS: Thirty-four (5%) of 710 GCTs occurred in patients older than 55 years (14/20 male/female; 56-83 years) in long bones (n = 24), vertebrae (n = 6), pelvis (n = 3), and metacarpal (n = 1). Imaging was classic in 26 of 27 cases; one case appeared malignant. Morphologic patterns included fibrosis (n = 29), bone formation (n = 19), cystic change (n = 8), necrosis (n = 8), foamy histiocytes (n = 7), and secondary aneurysmal bone cyst formation (n = 1). Mitoses ranged from 0 to 18 per 10 high-power fields. Six recurred; one patient developed metastasis. Four of five cases harbored H3F3A mutations. CONCLUSIONS: GCTs in patients 55 years or older share pathologic characteristics with those arising in younger adults. Fibrosis and reactive bone are common, potentially leading to diagnostic confusion in this population. No histologic features correlate with adverse outcome.

Capitate Chondroblastoma: A Case Report and Review of the Literature.

Background: Chondroblastomas are benign tumors that typically occur in the epiphysis of long bones. Carpal bone chondroblastomas are very rare and are known to have less aggressive behavior with no evidence of recurrence reported. Methods: We present a case of a recurrent chondroblastoma in the capitate that was treated with repeat curettage, application of phenol, and bone grafting. Results: At 3 years post surgery, the patient is disease free with excellent functional return. Conclusion: Chondroblastomas are rare within the carpus. We present a review of the literature detailing their occurrence and treatment.

Primary mucoepidermoid carcinoma of the lung with prominent clear cells.

Mucoepidermoid carcinoma of the lung is a rare malignancy of salivary gland-type origin. We report a case of a 21-year-old man with a right mainstem bronchus mass composed predominantly of clear cells. This case represents a rare primary pulmonary low-grade mucoepidermoid carcinoma positive for MAML2 rearrangement by fluorescence in situ hybridization with a prominent clear cell component.

Malignant transformation of polyostotic fibrous dysplasia with aberrant keratin expression.

Malignant transformation of fibrous dysplasia (FD) is exceedingly rare, occurring in less than 1% of all FD cases, and has been described in both monostotic and polyostotic forms of this entity. We report a case of a large proximal femur mass arising in a 45-year-old man. The biopsy revealed a high-grade pleomorphic malignancy that focally expressed multiple keratins. Based on the presence of keratin immunoreactivity, the morphologic differential diagnosis included metastatic sarcomatoid carcinoma. However, review of the clinical information revealed a history of polyostotic FD, and imaging findings were compatible with malignant transformation of FD. The resected neoplasm was biphasic and composed of areas of conventional FD admixed with a high-grade pleomorphic malignancy. Activating GNAS mutations were identified in both components. To the best of our knowledge, this is the first description of keratin expression in malignant transformation of FD.