Subchondral Osteoid Osteoma of a Metatarsal Bone: An Uncommon Variant in an Unusual Location

Osteoid osteoma (OO) is a benign bone-forming lesion leading to classical symptoms in the form of pain that aggravates during the night and is relieved by the treatment with salicylates. It constitutes 10% of benign skeletal neoplasms and is seen most often in males between the age group of 7 and 25 years. We report a rare case of subchondral OO of a metatarsal bone with unusual imaging features. This case illustrates the limitations of various imaging modalities in the diagnosis of bone tumors and the need for biopsy and histopathological analysis in difficult cases.

A Case Of Atypical Gastric Carcinoma With Osteoclast Like Giant Cells

Out of all the different types of neoplasms affecting the stomach, gastric carcinomas with Osteoclast-like Giant Cells (OGC) is one of the most uncommon. Although OGC are typically found in osseous neoplasms and tumors of the tendon sheath, few cases of extra-skeletal neoplasms with OGC have been documented. These typically involve organs such as the pancreas, gall-bladder, kidney, and breast. Even though the role of OGC in histogenesis of such tumors still remains unclear, their presence in extra-osseous neoplasms may indicate a certain level of immune reaction of the host towards the neoplastic transformation of normal tissue. We report a case of a 70-year-old Caucasian female hospitalized for evaluation of epigastric pain. Further examinations including endoscopy and biopsy of the stomach revealed gastric adenocarcinoma with OGC. This report also provides a brief insight into the possible immune reaction in such neoplasms

RARE-58. CONGENITAL METASTATIC CHORDOMA OF THE CLIVUS

Chordomas are rare midline axial skeletal neoplasms that typically present in adults. They are infrequent in childhood with typical localization in the spheno-occipital skull base. They are derived from remnants of the embryonic notochord. We present the case of 4 months old girl, who was born with „blueberry muffin” syndrome and was first negatively diagnosed for neuroblastoma and leukemia (two negative skin biopsies were performed) was admitted with axial laxity. In imaging testes there was a tumor of the scull base, metastases in the lungs and kidneys (that were not seen at previous assessments) and a small lesion in the heart. The third biopsy of skin lesion was performed and pathological examination revealed a neoplasm composed of cords, clusters, and chains of multivacuolated cells embedded within a myxoid matrix and separated by fibrous septa. No atypical and dedifferentiated features were present. Mitotic activity was not observed. Neoplastic cells showed the typical cytoplasmic immunostaining for EMA, S100 and cytokeratin AE1/AE3, strong nuclear brachyury expression, and retention of nuclear INI-1 expression. The diagnosis of chordoma was established. Neoplastic tissue and blood samples were obtained for molecular analysis using next generation sequencing, including germline mutations assessment (are ongoing). Chemotherapy as for soft tissue sarcomas was undertaken. Currently a patient is on treatment with improvement of neurological status.

Skeletal neoplasms of small dogs: a retrospective study and literature review

The skeletal neoplasms of small dogs are characterized poorly. In this retrospective study, the bone tumors of 37 small dogs (with body weights less than 15 kg), 74 large dogs (with body weights greater than 25 kg), and 134 small dogs previously reported in the literature were compared. Metastases accounted for about 25% of the bone tumors in small dogs, but less than 5% of the bone tumors in large dogs. In small dogs, osteosarcomas represented less than 50% of all skeletal neoplasms, frequently affected the axial skeleton, and had no apparent predilection for the distal radius. In this series and in the literature, fewer than 10 small dogs with appendicular osteosarcoma were treated with curative intent. Clinicians should use caution when extrapolating information on the biological behavior of osteosarcoma from large- and giant-breed dogs to small dogs.