An Unusual Histopathological Presentation of Mandibular Osteosarcoma.

Jaw osteosarcoma (JOS) is a rare, distinct variant that differ from long bone osteosarcoma (LBOS) in several aspects. JOS typically appears about twenty years later than LBOS, displays a lower propensity for metastasis to other organs, and exhibits better survival rates. The dissimilarities in clinical and biological behavior between JOS and LBOS are likely due, at least in part, to variations in their respective microenvironments.

Histologic Assessment of Lumbosacral Transitional Vertebrae Pseudoarticulation as a Source of Pain in Bertolotti Syndrome.

Background: Bertolotti syndrome (BS) is characterized by chronic pain and functional impairment associated with lumbosacral transitional vertebrae (LSTVs). The study aimed to investigate the histologic characteristics of the pseudoarticulation between the enlarged transverse process and sacrum seen in Castellvi 2a LSTV and explore the involvement of nervous tissue in pain generation.

Methods: Immunohistochemical analysis using S100 protein staining was performed to assess the presence of nerve tissue.

Cell Cycle Checkpoints p16 and p21-Strong Predictors of Clinicopathologic Outcomes in High-Grade Osteosarcoma.

Purpose: In this study, we used a series of immunohistochemical measurements of 2 cell cycle regulators, p16 and p21, to evaluate their prognostic value, separately and in combination, for the disease outcomes.

Method: A total of 101 patients with high-grade osteosarcoma were included in this study. Clinicopathologic data were collected, and immunohistochemistry for p16 and p21 was performed and interpreted by 3 independent pathologists.

Calcified chondroid mesenchymal neoplasm: report of a case involving the temporomandibular joint region and review of the literature.

The calcified chondroid mesenchymal neoplasm (CCMN) represents a recently recognized tumor type with only 50 well-documented cases in the English-language literature. Herein we report an additional case of CCMN presenting as a large mass in the temporomandibular joint region of a 41-year-old female. A review of previously reported cases and the current case of CCMN shows the following features: 1) average age 52 years (range 14-87 years) and an approximately even sex distribution; 2) most frequently involved sites: distal extremities (including foot, hand, wrist, forearm) (n=41) and temporomandibular joint/temporal/parotid region (n=9); 3) multilobular soft tissue tumor with chondroid to cartilaginous matrix, often grungy or lace-like calcifications, and variable cytologic atypia; 4) frequently detected FN1 rearrangement (n=15), including FN1 fusion with FGFR2 (n=7) or other receptor tyrosine kinases; 5) 2 reported local recurrences (after incomplete excision); 6) no reports of malignant biologic behavior.