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Ewing sarcoma (ES) of the spine is a rare childhood cancer with sparse literature on treatment outcomes. We aimed to describe survival outcomes and prognostic factors in patients with spinal ES treated at a single institute in a resource-challenged setting. We conducted a retrospective analysis of patients with spinal ES registered at a tertiary care oncology center between 2003-2019. Clinical patient data was retrieved from hospital records. Cox regression analysis was used to identify the association of baseline clinical parameters with event free survival (EFS) and overall survival (OS). A cohort of 85 patients was analyzed including 38 (45%) patients with metastatic disease. The median age was 15 years with 73% being male. Local therapy was administered in 62 (72.9%) patients with surgery alone in 8 (9.4%), radiotherapy alone in 36 (42.4%) and both in 18 (21.2%) patients. A higher proportion of males received local therapy than females (80.3% versus 59.1%; p  = 0.049). The median EFS and OS were 20.1 and 28.6 months, respectively. On univariable analysis, age ≤ 15 years, female sex, serum albumin ≤3.5 g/dL and hemoglobin ≤11 g/dL were associated with inferior EFS while younger age, female sex, hypoalbuminemia and metastatic disease were associated with inferior OS. On multivariable analysis, only hypoalbuminemia was predictive for inferior EFS (HR:2.41; p  = 0.005) while hypoalbuminemia (HR:2.06; p  = 0.033) and female sex (HR:1.83; p  = 0.046) were associated with inferior OS. We concluded that hypoalbuminemia confers poor prognosis in ES spine. Survival outcomes are poorer in females treated in our setting, possibly due to prevailing sex-based biases.

Benign fibro-osseous lesions (BFOLs) are a diverse group of lesions showing considerable degree of overlap with low grade osteosarcoma (LGOS). Further, de-differentiated osteosarcoma (DOS) is usually indistinguishable from conventional high-grade OS (COS) if LGOS foci are not identified. Thus, there is a need for adjunctive immunohistochemical markers to differentiate OS from benign FOLs as well as DOS from COS. This study evaluated the role of immunohistochemical expression of MDM2, CDK4, parafibromin, BCL-2 and Galectin-1 (Gal-1) in accurate characterization of benign FOLs and in differentiating them from OS. From our archives, we retrieved 101 tissue samples which were diagnosed as osteosarcoma (OS) /ossifying fibroma (OF) / fibrous dysplasia (FD) or fibrous hyperplasia (FH) and examined their immunohistochemical staining pattern with the aforementioned antibodies. MDM2 showed 100% specificity for diagnosing OS. CDK4 and Gal-1 showed linear increase in immunoexpression from benign BFOLs to OS. BCL-2 showed equivocal immunopositivity in OF and OS, but the positivity was higher than that observed in FD. The highest immunoexpression for parafibromin was seen in FD followed by OF and OS cases. Thus, MDM2 is most specific, and Gal-1 is most sensitive of all the markers studied in differentiating OS from benign mimics. Combination of these two markers can be used as an adjunct to conventional imaging and microscopy in accurate characterization of these lesions. Further MDM2 overexpression can differentiate DOS and COS., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Surface ultrastructures of giant cells (GCs) may help distinguish an aggressive tumor from an indolent giant cell tumor (GCT). This protocol describes a better way for ultrastructural surface imaging of GC from GCT of bone by scanning electron microscope (SEM). Fresh GCT samples collected in Dulbecco's modified Eagle medium (DMEM) are thoroughly washed to remove the blood and treated with collagenase to isolate the GCs. The collagenase-treated and critical point dried (CPD) samples yield a greater number of isolated GCs with better surface morphology, including membrane folding and micro-vesicular structures on the surface. Collagenase digestion and CPD should be performed for ultrastructural surface imaging of individual giant cells., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature.)

Giant cell tumor (GCT) of bone is a common benign lesion that causes significant morbidity due to the failure of modern medical and surgical treatment. Surface ultra-structures of giant cells (GCs) may help in distinguishing aggressive tumors from indolent GC lesions. This study aimed to standardize scanning electron microscopic (SEM) imaging of GC from GCT of bone. Fresh GCT collected in Dulbecco's Modified Eagle Medium was washed to remove blood, homogenized, or treated with collagenase to isolate the GCs. Mechanically homogenized and collagenase-digested GCs were imaged on SEM after commonly used drying methodologies such as air-drying, tetramethylsilane (TMS)-drying, freeze-drying, and critical point-drying (CPD) for the optimization of sample processing. The collagenase-treated samples yielded a greater number of isolated GC and showed better surface morphology in comparison to mechanical homogenization. Air-drying was associated with marked cell shrinkage, and freeze-dried samples showed severe cell damage. TMS methodology partially preserved the cell contour and surface structures, although the cell shape was distorted. GC images with optimum surface morphology including membrane folding and microvesicular structures on the surface were observed only in collagenase-treated and critical point-dried samples. Collagenase digestion and critical point/TMS-drying should be performed for optimal SEM imaging of individual GCs.

Myoepitheliomas (MEs) are uncommon tumours of the soft tissue with an intermediate biological behaviour and uncertain differentiation. Primary intra-osseous MEs are rare and occur predominantly in the axial and proximal appendicular skeleton in middle-aged patients. The morphological variation of the tumour cells and stromal metaplasia may cause considerable diagnostic confusion, especially when it occurs in an unusual location. A wide panel of immunohistochemical markers is required to exclude other histological mimics. A 37-year-old male presented with a recurrent swelling in the right middle finger for 1-month duration. Radiographic images showed an expansile, lytic, intra-osseous lesion with high signal intensity on T2W fat-suppressed MR images in the proximal phalanx of the right middle finger without cortical breach, highly suggestive of an enchondroma. Histopathology revealed a lobulated tumour comprising of polygonal to spindle cells in groups and cords in a chondromyxoid stroma. No cellular atypia was noted. The tumour cells were immunopositive for epithelial membrane antigen (EMA), p63, S100 and smooth muscle actin (SMA), compatible with the diagnosis of an intraosseous ME. The proximal phalanx of the right middle finger was excised, revealing a similar tumour, and the patient has been on regular follow-up for the last 18 months without any recurrence. Primary intra-osseous MEs are extremely rare, and this is the second reported occurrence in small bones. A differential diagnosis of ME should be kept for enchondroma-like lesions of the bone for proper histopathological assessment and accurate diagnosis. Documentation of such cases and follow-up will enhance our understanding of their clinical course and prognosis.

Malignant peripheral nerve sheath tumors (MPNSTs) are uncommon sarcomas that originate from a peripheral nerve or neurofibroma either spontaneously or in association with neurofibromatosis type 1. MPNSTs account for approximately 5% of all soft tissue malignancies. The tumor is commonly seen in the extremities and trunk. Most of these tumors are high-grade with the potential to recur and metastasize. Common metastatic sites include the lungs, bone, and pleura. Primary intraosseous MPNST is rare, and the diagnosis of intraosseous MPNST, especially in an unusual location is difficult because of its cellular origin, histomorphological similarities with other sarcomas, and bone is the most common site for metastasis. We report an unusual case of MPNST of the calcaneus in a young male.

Background: Epithelioid hemangioma (EH) is a rare benign vascular lesion of soft tissue and bone, characterized by endothelial cells with epithelioid or histiocytoid appearance. Though tubular bones, flat bones, vertebra and short bones are common sites for this lesion, the epiphyseal involvement is extremely rare. We present an unusual case of EH of the distal femur in a young boy., Case Report: A 12-year-old boy who had congenital talipes equinovarus of the right foot presented with progressively increasing pain in the right lower thigh for six months. Physical examination revealed muscular atrophy of the right lower limb and a moderately tender swelling in the medial aspect of the right knee without restriction of knee movement. An X-ray revealed an osteolytic lesion, which appeared iso- and hypointense on T1W and hyperintense on T2W MRI images in the distal epiphysis and adjacent metaphysis of the right femur. A radiological diagnosis of chondroblastoma was entertained. The patient was treated with curettage and bone grafting. Histopathology showed a tumor composed of thin-walled arteriolar capillaries lined by large, polyhedral epithelioid endothelial cells with vesicular nuclei, finely distributed nuclear chromatin, and moderate amount of eosinophilic cytoplasm. The endothelial cells were strongly immunopositive for CD34. Mitotic activity was low and the Ki-67 proliferative rate was <2%. A diagnosis of EH was made. EH is a benign lesion and it should be differentiated from its histologically similar malignant counterparts such as epithelioid hemangioendothelioma and epithelioid angiosarcoma as the lesion can be successfully treated with curettage or resection.