Periosteal Myxoid Leiomyosarcoma Histologically Mimicking Extraskeletal Myxoid Chondrosarcoma: Report of a Case with Histopathological and Cytopathological Comparison with Extraskeletal Myxoid Chondrosarcoma

Myxoid leiomyosarcoma (MLS) is a rare variant of leiomyosarcoma, with most cases occurring in the uterus. A case of MLS arising in the periosteal region of the tibia, mimicking extraskeletal myxoid chondrosarcoma (EMC), is described. The evaluation included histological and cytological comparison with EMC. The patient was a 77-year-old man with a palpable mass at the anterior aspect of the right lower leg. After diagnosis by cytopathology and biopsy examination, a wide resection was performed. The resulting cytological smears were composed primarily of spindle-shaped tumor cells in a myxoid and hemorrhagic background. Histologically, the tumor showed abundant myxoid matrix and tumor cells proliferating in a cord-like to reticular pattern, exhibiting a lace-like arrangement that mimicked EMC. Although immunohistochemical findings suggested leiomyosarcoma, a diagnosis of EMC eventually was excluded by the lack of a split signal when assessed for a rearrangement of NR4A3 by chromogenic in situ hybridization. Despite histological similarity to EMC, characteristic cytological findings of EMC such as epithelioid structures with a cord-like pattern and chondroblast-like lacunar structures were not observed in the smears of this patient’s MLS. We propose that cytopathological examination of bone and soft tissue lesions is useful as a diagnostic tool in similar cases. A total diagnostic workup, including clinical, radiographic, cytopathological, histopathological, and molecular findings, is needed to ensure an accurate final diagnosis and to reduce diagnostic error.

Sustained response to imatinib in patient with extraskeletal myxoid chondrosarcoma and novel KIT mutation

A 55-year-old woman presented with a 3-month history of right groin swelling, discomfort and impaired mobility. On examination, a palpable mass was noted both to the right of midline in the lower abdomen and in the right groin. MRI of the pelvis showed two masses involving the anterior abdominal wall and right groin, as well as lymph node involvement. CT imaging revealed multiple bilateral pulmonary metastases. Pathology demonstrated a myxohayline stroma morphology. Tumour was also notable for NR4A3 gene region rearrangement and mutation in KIT exon 11 at position c.1669 T>G. Based on these findings, she was diagnosed with extraskeletal myxoid chondrosarcoma (EMC). The patient has been on imatinib, a tyrosine kinase inhibitor with activity against KIT, for 3 years with stable disease. Metastatic EMC is generally treated with surgical resection and perioperative radiation therapy with adjuvant chemotherapy and is associated with poor prognosis.

Novel RGAG1-BCOR gene fusion revealed in a somatic soft tissue sarcoma with a long follow-up

BCOR-rearranged sarcomas are rare and belong to the Ewing-like sarcomas (ELS). Their morphology and histopathological features make the diagnosis challenging. We present a case, initially diagnosed as an unusual extraskeletal myxoid chondrosarcoma (EMC). A 54-year-old male patient developed an asymptomatic swelling of the lower leg. Imaging showed a 9.5-cm large intramuscular soft tissue mass. Due to its morphological and immunohistochemical profile on biopsy, it was initially diagnosed as an EMC. The patient was treated by complete resection and adjuvant radiotherapy and remained free of tumor at 7 years follow-up. Using next-generation sequencing (NGS), we retrospectively identified RGAG1-BCOR gene fusion (confirmed by RT-PCR), which has not been described in somatic soft tissue tumors so far. This finding broadens the spectrum of partner genes in the BCOR-rearranged sarcomas in a tumor with a well-documented, long clinical follow-up.

Extraskeletal myxoid chondrosarcoma of thigh: a rare case report

Extraskeletal myxoid chondrosarcoma (EMC) are a rare entity of soft tissue tumors that occur predominantly in soft tissue of lower extremities. Here we present a case of 45-year-old female presented with left thigh swelling. MRI finding suggested primary neoplastic lesion. Fine needle aspiration cytology (FNAC) suggested myxoid soft tissue neoplasm/sarcoma. Morphological examination revealed typical extraskeletal myxoid chondrosarcoma with strong immunoreactivity for vimentin and focal immunoreactivity for epithelial membrane antigen (EMA).

Surgery Treatment Improved the Overall Survival Rate in Locoregional Myxoid Leiomyosarcoma than Other Myxosarcomas in the United States

Myxosarcomas are rare malignant tumors of soft connective tissues, classified into various subtypes, including myxoid liposarcoma, myxoid chondrosarcoma, and myxoid leiomyosarcoma. In this study, we proposed to study the demographic, tumor characteristics, and overall survival rate and compared the treatment modalities between these cancers. Patient data collected based on locoregional metastasis presentation of the abovementioned tumors with a cutoff study of survival duration up to 10 years were obtained from the SEER database during 1975-2016. Our results indicated that elderly patients and females were more in locoregional myxoid leiomyosarcoma than myxoid liposarcoma and myxoid chondrosarcoma with locoregional metastasis. The white race represented the most patients who suffered from these cancers than other races. The heart is the primary site for the abovementioned cancers, in addition to the female genitals to the myxoid leiomyosarcoma. Myxoid liposarcoma and myxoid chondrosarcoma patients with locoregional metastasis were suffering from grade II, while locoregional myxoid leiomyosarcoma patients with blank grading were due to missed data. Surgery was the most common treatment modality in this study compared with radiotherapy and chemotherapy. Kaplan-Meier analysis showed a significant difference in survival time between the three subtypes by using histology, and myxoid leiomyosarcoma showed prolonged survival than others. Elderly, female, white, unknown grade, surgery, no radiation, and no chemotherapy variables were independent factors associated with overall survival among these cancers. Multivariate analysis also showed significant differences in overall survival between the three tumors by histology, and myxoid leiomyosarcoma was with a better prognosis than others. Multivariate analysis of locoregional myxoid leiomyosarcoma showed the statistical significance of black race, grade, and radiotherapy, indicating them as independent prognostic factors of locoregional myxoid leiomyosarcoma. We conclude that surgery was the primary treatment modality against these cancers than radiotherapy and chemotherapy. And the locoregional myxoid leiomyosarcomas showed a better prognosis and higher survival rate than locoregional myxoid liposarcoma and locoregional myxoid chondrosarcoma.

Primary Extraskeletal Myxoid Chondrosarcoma: A Case Report

Extraskeletal Myxoid Chondrosarcoma (EMC) is a rare malignant soft tissue sarcoma with uncertain differentiation, most often seen in males. The incidence is 3% of all soft tissue tumours with limited literature available on its cytological features. EMC may arise from lower extremities, upper extremities, retroperitoneum, pelvis, and buttocks. This case report was an effort to understand the role of Fine Needle Aspiration Cytology (FNAC), histopathology and immunochemistry in the diagnosis of EMC. Authors hereby report a case of a 70-year-old male patient with slow-growing soft tissue swelling on the back just behind the right shoulder who was referred for FNAC. Patient complete history and clinical findings were recorded. Radiological images were suggestive of malignant soft tissue neoplasm with no involvement of underlining bone. FNAC reveled tumour cells which appeared monotonous and they were seen in a myxoid stroma background. Subsequently, the excised lesion was sent for histopathological examination and the report revealed the presence of abundant chondromyxoid matrix material within which were found numerous elongated spindly shaped cells. These cells had moderately pleomorphic elongated nuclei with focal solid fibrocollagenous areas along intersecting fascicles of the moderately pleomorphic spindly cell. Few of these cells had multilobulated bizarre nuclei with nuclear inclusions. Immunohistochemical stains showed diffuse positivity for S-100, vimentin, and focally positive for Epithelial Membrane Antigen (EMA). The FNAC, histopathology and immunohistochemical features confirm the diagnosis of EMC on right shoulder. It’s a rare tumour whose diagnosis is made depending on history, clinical location, growth pattern, histopathology, and immunohistochemistry.