Squamous differentiation and cytokeratin expression in an osteosarcoma: a case report and review of the literature

Investigating surface proteins and antibody combinations for detecting circulating tumor cells of various sarcomas

Circulating tumor cells (CTCs) have gathered attention as a biomarker for carcinomas. However, CTCs in sarcomas have received little attention. In this work, we investigated cell surface proteins and antibody combinations for immunofluorescence detection of sarcoma CTCs. A microfluidic device that combines filtration and immunoaffinity using gangliosides 2 and cell surface vimentin (CSV) antibodies was employed to capture CTCs. For CTC detection, antibodies against cytokeratins 7 and 8 (CK), pan-cytokeratin (panCK), or a combination of panCK and CSV were used. Thirty-nine blood samples were collected from 21 patients of various sarcoma subtypes. In the independent samples study, samples were subjected to one of three antibody combination choices. Significant difference in CTC enumeration was found between CK and panCK + CSV, and between panCK and panCK + CSV. Upon stratification of CK+ samples, those of metastatic disease had a higher CTC number than those of localized disease. In the paired samples study involving cytokeratin-positive sarcoma subtypes, using panCK antibody detected more CTCs than CK. Similarly, for osteosarcoma, using panCK + CSV combination resulted in a higher CTC count than panCK. This study emphasized deliberate selection of cell surface proteins for sarcoma CTC detection and subtype stratification for studying cancers as heterogeneous as sarcomas.

Cytokeratin-Positive Osteosarcoma Simulating Sarcomatoid Metastatic Carcinoma

Osteosarcoma, the most common primary malignant bone tumor, rarely stains positive for epithelial markers such as cytokeratin on immunohistochemical analysis. We describe a 52-year-old man with a destructive distal femoral metaphyseal lesion who was initially treated for metastatic sarcomatoid carcinoma based on extensive radiographic and histopathologic evaluation. Ultimately, wide resection of the distal femur was performed, revealing high-grade conventional osteosarcoma with intense and diffuse cytokeratin positivity. Such immunohistochemical staining in osteosarcoma is rare, making it difficult to distinguish cytokeratin-positive osteosarcoma from metastatic carcinoma. The presence of a cytokeratin-positive bone neoplasm with malignant osteoid formation on histological studies as well as integration with clinical and radiologic data can help confirm osteosarcoma as the ultimate diagnosis.

Syringic acid may attenuate the oral mucosal carcinogenesis via improving cell surface glycoconjugation and modifying cytokeratin expression

Syringic acid (SRA) is an excellent anti-oxidant and anti-cancer property in various in vitro and in vivo studies. In the present study was modifying effect of SRA on 7,12-dimethylbenz(a)anthracene (DMBA) induced cell surface glycoconjugates (GCs) abnormalities in the plasma and buccal mucosa of golden Syrian hamster buccal pouch carcinogenesis (HBPCs). Topical application of DMBA three times a week for 10 weeks on the buccal pouches of the hamsters resulted in well developed squamous cell carcinoma. GCs status was assessed biochemically, histological and immunoexpression pattern of cytokeratin (CK) in the buccal mucosa of the DMBA treated hamsters. Elevated levels of GCs and CK expression were observed in DMBA alone treated hamsters. Oral pre-administration of SRA (50 mg/kg bw) positively modulates the GCs levels and CK expressions to near normal. The present findings suggested that SRA can protect cell surface GCs and CK expression during DMBA induced HBPCs.

Fibroblastic osteosarcoma with epithelioid and squamous differentiation in a dog

A fibroblastic osteosarcoma with epithelioid and squamous differentiation in the distal femur of a 9-y-old spayed female Greyhound dog is described. Grossly, the tumor consisted of a pale-white, firm-to-hard mass that replaced the medullary and cortical areas of the distal end of the right femur. Histologically, the mass was composed predominantly of spindle cells admixed with areas of mineralized and non-mineralized osteoid matrix that were surrounded by stellate osteoblasts and scattered multinucleate giant cells, consistent with the diagnosis of a fibroblastic osteosarcoma. In addition, well-demarcated clusters of neoplastic epithelioid cells and foci of squamous differentiation with keratin pearls were present throughout the neoplasm. The spindle cells, epithelioid cells, and areas of squamous differentiation expressed cytoplasmic immunostaining for osteocalcin and osteonectin. The spindle cells and epithelioid cells were also immunopositive for vimentin. Epithelioid cells also expressed occasional cytoplasmic immunostaining for pancytokeratin (PCK) Lu-5, and areas of squamous differentiation were immunoreactive for PCK Lu-5 and high molecular weight CK; these areas were inconsistently immunoreactive for CK 5-6 and immunonegative for low molecular weight CK. Foci of squamous differentiation were not located within blood or lymphatic vessels, given that no immunoreactivity for factor VIII-related antigen was observed around these areas. A thorough autopsy and an evaluation of the medical history excluded a primary carcinoma or other neoplasm elsewhere in the dog. The findings were consistent with a diagnosis of fibroblastic osteosarcoma with epithelioid and squamous differentiation.

[Lymph node metastasis of osteosarcomas]

Lymph node metastasis of osteosarcomas is a rather rare phenomenon; according to different authors, the incidence of lymph node metastasis is 4 to 11%. The detection of lymph node metastases in osteosarcoma is associated with a significant reduction in the 5-year survival of patients and allows its classification as clinical stage IV tumor. The risk factors for lymph node metastases in patients with bone sarcomas are age (≥64 years), gender (female), nosological entity (undifferentiated pleomorphic sarcoma, osteosarcoma, chondrosarcoma), tumor depth (muscle, bone), and the size of primary tumor (>5 сm). The mechanism of lymph node metastasis of osteosarcomas seems to be related to mesenchymal-to-epithelial transition.

Clinicopathological features of five unusual cases of intraosseous myoepithelial carcinomas, mimicking conventional primary bone tumours, including EWSR1 rearrangement in one case

Primary intraosseous myoepithelial tumours, including carcinomas are rare tumours. The concept of histopathological spectrum of these tumours is evolving. We describe clinicopathological and immunohistochemical features of five myoepithelial carcinomas, including molecular cytogenetic results in one case. There were five male patients within age-range of 8-40 years (median = 26). Four tumours occurred in the long bones, including two tumours, each, in the femur and fibula, respectively, while a single tumour occurred in the proximal phalanges. Tumour size (n = 3 cases) varied from 5.6 to 8.6 cm. On radiological imaging, most tumours appeared as expansile, lytic and destructive lesions. Two tumours appeared as sclerotic lesions. Two cases were referred with diagnoses of chondrosarcomas and a single case was referred with two different diagnoses, including an adamantinoma and an osteosarcoma. Histopathological examination in all these cases showed multinodular tumours comprising mostly polygonal cells, exhibiting moderate nuclear atypia and interspersed mitotic figures within a stroma containing variable amount of myxoid, chondroid, hyalinised and osteoid-like material. Three tumours revealed prominent squamous differentiation. By immunohistochemistry, tumour cells were positive for EMA (5/5), pan CK (AE1/AE3) (3/3), CK5/6 (4/4), CK MNF116 (1/1), S100 protein (5/5) and GFAP (3/5). The first tumour revealed EWSR1 rearrangement. The first patient, 10 months after tumour resection and a simultaneous lung metastatectomy, is free-of-disease (FOD). The second patient, 11 months after tumour resection is FOD. The third and fourth patients underwent wide resections and are on follow-up. The fifth patient underwent resections, including a lung metastatectomy. Primary intraosseous myoepithelial carcinomas are rare and mimic conventional primary bone tumours. Some primary intraosseous myoepithelial carcinomas display EWSR1 rearrangement. Squamous differentiation may be considered as an addition to their evolving histopathological spectrum. Immunohistochemical stains constitute as a necessary tool for arriving at the correct diagnosis in such cases, which has treatment implications. Surgical resection remains the treatment mainstay.

Osteosarcoma of the femur mimicking Ewing sarcoma/primitive neuroectodermal tumour on biopsy and metastatic carcinoma on resection

Osteosarcoma (OS) is known to have several morphological appearances, small cell osteosarcoma and epithelioid osteosarcoma being two well recognized patterns. The former can be mistaken for a Ewing sarcoma/primitive neuroectodermal tumour (ES/PNET), whereas the latter mimics metastatic carcinoma. Herein we present an osteosarcoma in a 17-year-old girl that was diagnosed as an ES/PNET on biopsy; however, the resected specimen revealed a very unusual morphology mimicking a metastatic carcinoma with a sex cord stromal tumour-like pattern.