Surgical Excision of Thoracic Osteoblastoma with Secondary Aneurysmal Bone Cyst from a 12-Year-Old Child.

INTRODUCTION: Osteoblastoma is a primary benign tumour which commonly presents in the younger population during the second decade of life. However, more aggressive osteoblastomas may present with features of aneurysmal bone cyst, and these can occur at uncommon locations. CASE PRESENTATION: We report the case of a 12-year-old child having an osteoblastoma on the left side of T11 with secondary aneurysmal bone cyst presenting with neurological deficits and myelopathic symptoms. Surgical debulking of the lesion with decompression laminectomy and posterior instrumentation of the spine was performed. The child is currently recovering well with improvement of neurological deficits. DISCUSSION/CONCLUSION: Osteoblastoma with aneurysmal bone cyst of the thoracic spine is a rare condition with few reports in the literature, and surgical intervention with complete excision has been demonstrated here with recovery of neurological function.

The 1000 Mitoses Project: A Consensus-Based International Collaborative Study on Mitotic Figures Classification.

Introduction. The identification of mitotic figures is essential for the diagnosis, grading, and classification of various different tumors. Despite its importance, there is a paucity of literature reporting the consistency in interpreting mitotic figures among pathologists. This study leverages publicly accessible datasets and social media to recruit an international group of pathologists to score an image database of more than 1000 mitotic figures collectively. Materials and Methods. Pathologists were instructed to randomly select a digital slide from The Cancer Genome Atlas (TCGA) datasets and annotate 10-20 mitotic figures within a 2 mm2 area. The first 1010 submitted mitotic figures were used to create an image dataset, with each figure transformed into an individual tile at 40x magnification. The dataset was redistributed to all pathologists to review and determine whether each tile constituted a mitotic figure. Results. Overall pathologists had a median agreement rate of 80.2% (range 42.0%-95.7%). Individual mitotic figure tiles had a median agreement rate of 87.1% and a fair inter-rater agreement across all tiles (kappa = 0.284). Mitotic figures in prometaphase had lower percentage agreement rates compared to other phases of mitosis. Conclusion. This dataset stands as the largest international consensus study for mitotic figures to date and can be utilized as a training set for future studies. The agreement range reflects a spectrum of criteria that pathologists use to decide what constitutes a mitotic figure, which may have potential implications in tumor diagnostics and clinical management.

A single tertiary institution review of the international system for serous fluid cytopathology and the impact of cell block and ancillary studies on its performance.

INTRODUCTION: We sought to assess the utility of the International System for Serous Fluid Cytopathology (TIS) in the context of our department's routine practice. MATERIALS AND METHODS: We examined 1028 archived effusion cytology (pleural, peritoneal, and pericardial) cases from 2018 to 2019, and re-classified them along the international system into the following diagnostic categories: nondiagnostic (ND), negative for malignancy (NFM), atypia cells of undetermined significance (AUS), suspicious for malignancy (SFM), and malignant (MAL). RESULTS: The full distribution of the cases examined was as follows: ND 2.0%; NFM 66.1%; AUS 6.0%; SFM 4.7%; MAL 21.2%. Overall risk of malignancy for each category was calculated as: ND 30.0%; NFM 18.0%; AUS 61.9%; SFM 100%; MAL 94.4%. The overall performance attributes of TIS were as follows: sensitivity 57.1%; specificity 98.3%; positive predictive value 94.4%; negative predictive value 82.0%; diagnostic accuracy 84.5%. CONCLUSIONS: The new classification was simple and intuitive to use and our results appear to fall within the expected ranges of the new guidelines, with risk of malignancy and accuracy comparable to similar studies. The availability of a cell block allowed for refinement of the diagnosis in a majority of cases with equivocal cytology, though this was dependent on the cell yield.

Surprise Lymph Node Histology in a Patient with Ovarian Serous Carcinoma.

We report a case of a sixty-three-year-old Chinese female with a known past history of primary, biopsy-diagnosed, ovarian high-grade serous carcinoma. Following three cycles of chemotherapy, she underwent total hysterectomy, bilateral salpingo-oophorectomy cytoreductive surgery with lymphadenectomy, and multiple peritoneal biopsies. In this situation, the lymph nodes would be expected to demonstrate possible residual metastatic serous carcinoma with or without chemotherapy effect. The final diagnostic assessment in the lymph nodes, in this patient, however, was a rare combination of the following pathologies: metastatic serous carcinoma, with areas of chemotherapy effect, and incidental PEComatosis, focally in association with endometriosis, both within lymph nodes and surrounding connective tissue. PEComas have been described in patients with the tuberous sclerosis complex, but the current patient was not known to suffer from this condition. This case is also unusual, as although PEComas have been described as arising in the female genital tract, the associated phenomenon of endometriosis is exceedingly rare, and this is the first known reported case of lymph nodes harbouring a similar combination of pathologies.