Myopericytoma of the hand.

Myopericytoma is a rare benign smooth-muscle cell neoplasm of the subcutaneous soft tissues that is primarily found in young adults with a male predominance. We present the clinical, radiologic, and histopathologic features of a longstanding myopericytoma of the hand. We emphasize the features that help the radiologist and pathologist to accurately characterize this entity.

Investigating the behavior of ultratrace levels of nanoparticulate and ionic silver in a seawater mesocosm using single particle inductively coupled plasma - mass spectrometry.

Silver nanoparticles (AgNPs) nowadays appear in close to 24% of consumer products that contain engineered nanomaterials. Thus, they are expected to be released into the environment, where their fate and effect are still undetermined. Considering the evidenced efficacy of the single particle Inductively Coupled Plasma - Mass Spectrometry (sp ICP-MS) technique in the study of nanomaterials, this work reports on the use of sp ICP-MS along with an online dilution sample introduction system for the direct analysis of untreated and spiked seawater samples, as part of a larger scale experiment studying the fate of Ag (ionic and nanoparticles) in seawater mesocosm systems.

Isolation of Bacterial Extracellular Vesicles and Identification of Their Protein Cargo.

Bacterial membrane vesicles (BMVs) are important effectors in the pathogenesis, virulence, and biofilm formation during different bacterial infections. Because of their structure, BMVs can be applied as drug delivery systems (DDS) or in the production of immunogenic vaccines against different untreated diseases. In this sense, different antigens or immune stimulator molecules, such as proteins can be extracted for the development of such vaccines.

Rosai-Dorfman Disease of Bone and Soft Tissue.

Context.—: Rosai-Dorfman disease is a rare histiocytic proliferative disorder of unknown pathogenesis that may be diagnostically difficult in extranodal sites. It is commonly an unsuspected diagnosis when arising in bone and soft tissue, especially when it presents without associated lymphadenopathy.

Epiphyseal Ewing Sarcoma in a skeletally mature patient: A case report and review of the literature.

While Ewing sarcoma of bone is the second most common primary osseous malignancy in childhood where it typically involves the diaphysis or metadiaphyses of long bones of skeletally immature patients, primary epiphyseal involvement of the long bone in skeletally mature patients is rare with no cases reported in the literature to our knowledge, rendering this case the first of its kind. We present the first case of primary Ewing Sarcoma of the epiphyses of the long bones in a skeletally mature 20-year-old male patient. The patient initially presented with left knee stiffness and pain that was empirically treated with non-steroidal anti-inflammatory medications.

Giant Cell Tumor of Distal Radius After Open Reduction Internal Fixation for Distal Radius Fracture.

Case: A 77-year-old woman presented with volar wrist pain 1.5 years after undergoing distal radius volar locked plating for fracture. Radiographs and CT were notable only for plate prominence, and she was admitted for removal of hardware.

NFAT restricts osteochondroma formation from entheseal progenitors.

Osteochondromas are common benign osteocartilaginous tumors in children and adolescents characterized by cartilage-capped bony projections on the surface of bones. These tumors often cause pain, deformity, fracture, and musculoskeletal dysfunction, and they occasionally undergo malignant transformation. The pathogenesis of osteochondromas remains poorly understood.

A 15-Year-Old Male Baseball Player With a Mass in the Brachialis Muscle.

A 15-year-old boy presented with a mass in his right arm after suffering a minor injury playing baseball. He had been diagnosed with a hematoma. There was no other outstanding medical/surgical history.

Chondroid Syringoma of the Foot: A Rare Diagnosis.

Chondroid syringoma is a rare tumor with the potential for malignant transformation and distant metastasis. The site of predilection for benign chondroid syringoma is the head and neck region, and it is less likely to involve the foot. In contrast, malignant chondroid syringoma is more commonly encountered in the extremities and is characterized by rapid growth, local invasion, and distant metastasis.

Recurrent temporal bone tenosynovial giant cell tumor with chondroid metaplasia: the use of imaging to assess recurrence.

Tenosynovial giant cell tumor (TGCT) is a benign proliferative lesion of unclear etiology. It is predominantly monoarticular and involves the synovium of the joint, tendon sheath, and bursa. TGCT of the temporomandibular joint (TMJ) is rare and aggressive resulting in destruction of surrounding structures.

Myofibroblastic differentiation of stromal cells in giant cell tumor of bone: an immunohistochemical and ultrastructural study.

The nature of the mononuclear stromal cells (MSCs) in giant cell tumor of bone (GCTB) has not been thoroughly investigated. The purpose of this study was to evaluate the degree and significance of myofibroblastic differentiation in 18 cases of GCTB by immunohistochemistry (IH) and/or electron microscopy (EM). All immunostained cases were found positive for smooth muscle actin (SMA) and/or muscle specific actin (MSA), most in 1-33% of the MSCs.

Intraosseous pseudotumor of the distal radius in a patient with hemophilia: case report.

Hemophilic pseudotumors are rare, particularly when they occur in the distal extremity of an adult patient. We present the case of a 68-year-old man with well-controlled factor VIII deficiency who presented with a lytic lesion of the distal radius that was identified as an intraosseous pseudotumor.

Benign bone tumors--recent developments.

Benign bone tumors frequently pose a diagnostic challenge for general surgical pathologists. Accurate pathologic diagnosis requires careful clinical and radiological correlation. The most significant recent advances in some benign bone tumors have occurred at the molecular and cytogenetic level.

Chondroid tenosynovial giant cell tumor: a clinicopathological and immunohistochemical analysis of 5 new cases.

Tenosynovial giant cell tumor (TGCT) arises from the synovium of joints or tendon sheaths. Chondroid metaplasia in TGCT is rare with only 4 well-documented cases reported in the literature. The authors describe the morphological features and immunophenotype of 5 new cases of chondroid TGCT emphasizing a broader range of matrix patterns in these tumors and an expanded immunophenotype, specifically, staining for clusterin and podoplanin which have recently been found to be expressed in conventional TGCTs.

Chronic lymphocytic leukemia/small lymphocytic lymphoma presenting as septic arthritis of the shoulder.

We report a case of a 53-year-old man presenting with shoulder pain mimicking septic arthritis. Laboratory findings were atypical. Biopsy performed to assess for possible osteomyelitis demonstrated chronic lymphocytic leukemia/small lymphocytic lymphoma.

Multifocal renal oncocytoma in a patient with Von Hippel-Lindau mutation.

Von Hippel-Lindau disease (VHL) is a rare genetic disease with a lifetime risk of clear cell renal cell carcinoma in approximately 70% of cases. We present a case of a 63-year-old man with bilateral, multifocal renal masses. Genetic testing results were consistent with a VHL deletion.

Giant cell tumor of soft tissue with pulmonary metastases: pathologic and cytogenetic study.

Giant cell tumor of soft tissue (GCTST) has gained general acceptance as an uncommon but distinct primary soft tissue tumor since it was first described in 1972. GCTST is predominantly seen in adults and typically shows uniformly dispersed osteoclast-like giant cells admixed with oval to polygonal mononuclear cells. It usually follows a benign clinical course, although the malignant variant has been described in cases in which the mononuclear cells demonstrate obvious dysplastic features.

Colonic histoplasmosis in acquired immunodeficiency syndrome mimicking carcinoma.

Four cases of colonic histoplasmosis in patients with acquired immunodeficiency syndrome mimicking other diseases, primarily colonic adenocarcinoma, are presented. This topic has been extensively discussed from the medical and radiologic standpoint, but very few publications are found in the pathology literature. Emphasis is made on the discussion of the clinical manifestations; endoscopic, radiologic, and pathologic characteristics; differential diagnosis; and treatment.