Wenger, Doris E.

Abstract: Kimura disease typically presents with painless head and neck swelling in young adults of Asian descent, accompanied by peripheral eosinophilia and elevated serum IgE. We report a case of Kimura disease in a woman in her early 30s presenting with a slowly enlarging epitrochlear mass, diffuse encasement of the median and medial brachial cutaneous nerves, and a concurrent prurigo nodularis-like papular rash affecting all 4 extremities. The diagnosis required over 1 year of investigation and 5 tissue specimens, including 2 nondiagnostic core-needle biopsies, before near total excision was performed. The excision revealed characteristic histopathologic features, including hyperplastic reactive secondary lymphoid follicles with preserved architecture, a marked eosinophilic infiltrate with eosinophilic microabscesses, postcapillary venule proliferation, and patternless stromal fibrosis. Immunohistochemistry demonstrated a raised IgG4:IgG plasma cell ratio of approximately 1:1, with 150–200 IgG4-positive plasma cells per high-power field, raising the differential of IgG4-related disease; however, the absence of storiform fibrosis and obliterative phlebitis, combined with the clinical and serologic profile, favored Kimura disease. This case is notable for its rare epitrochlear location, extensive neural involvement, concurrent diffuse cutaneous eruption, and histopathologic overlap with IgG4-related disease, highlighting the diagnostic challenges posed by atypical presentations of Kimura disease.

BACKGROUND Ecchordosis physaliphora (EP), a benign extraosseous notochordal remnant, has been found in 0.4%–2% of autopsies. It most commonly occurs on the dorsal surface of the clivus and is rarely symptomatic. Extraosseous notochordal lesions involving the spine are also rare, with the majority being diagnosed as chordoma. OBSERVATIONS The authors report a case of an extradural extraosseous notochordal lesion within the left L5–S1 nerve root foramen resulting in left lumbar L5 radiculopathy in a 46-year-old woman. Microdecompression at the left lumbar L5–S1 level permitted successful removal of the lesion and complete resolution of radiculopathy. The combined histopathological and retrospective imaging findings were felt to be consistent with EP. Thirty-nine-month follow-up imaging revealed no recurrence of the lesion, and the patient remains asymptomatic at last follow-up. LESSONS Challenges in diagnosing EP, particularly distinguishing it from extraosseous chordoma, and the implications of diagnostic terminology on the management of these lesions are discussed. https://thejns.org/doi/10.3171/CASE26203

Abstract Background We retrospectively assessed volumetric response of myxoid liposarcoma (MLPS) with preoperative radiotherapy (RT) and sought to identify disease and treatment characteristics associated with response. Patients and methods We identified all patients with a histologic diagnosis of MLPS who received preoperative RT from 2013 to 2021 at our institution. We used cone beam computed tomography (CBCT) to assess changes in tumor volume and greatest dimension during treatment. Tumors were contoured on CBCT images prior to treatment and at the end of each week of RT. Percentage change in tumor volume and greatest dimension were calculated based on pre-treatment and final week contours. Patients with tumors incompletely visualized on CBCT were excluded from volume analysis but included on greatest dimension analysis. Magnetic resonance imaging (MRI) was used to evaluate pre- and post-RT radiographic features. Surgical pathology was reviewed to record pathologic characteristics. Results Twenty patients met inclusion criteria. Most tumors (18/20) were low grade. The most frequent dose/fractionation scheme was 50 Gy in 25 fractions (16/20), with 3 patients receiving 36 Gy in 18 fractions. Median pre-RT volume and greatest dimension were 120 cc (interquartile range [IQR]: 56–399) and 11.2 cm (IQR: 8.4–14.1), respectively. Median percentage change in volume and greatest dimension were -37% (IQR: -57 to -29) and -10% (IQR: -20 to -7). All evaluable tumors decreased in volume during RT. Between pre- and post-RT MRI, most patients had a decrease in intratumoral (16/20) and peritumoral edema (11/20). Sixteen patients exhibited extensive pathologic response. There were no significant associations between radiographic and pathologic features and volumetric change. Local failure at 3 years was 9% (95% confidence interval: 1–59). Conclusions We report significant decreases in MLPS tumor size during preoperative RT. There may be a role for adaptive RT planning to reduce target volumes and minimize RT-associated morbidity.

Myoepithelial tumors are typically characterized by distinct molecular profiles that have been shown to correlate with their anatomical locations. EWSR1 or FUS rearrangements are common in cutaneous, soft tissue and bone tumors, whereas salivary gland myoepithelial tumors are frequently associated with PLAG1 and HMGA2 alterations. This apparent molecular divergence led some previous studies to doubt a common pathogenetic relationship between myoepithelial tumors of soft tissue and bone with their salivary gland counterparts. Herein, we present primary intraosseous myoepithelioma harboring HMGA2::WIF1 fusion. This fusion has been previously identified in a range of salivary gland myoepithelial tumors including myoepitheliomas, myoepithelial carcinomas arising from pleomorphic adenomas, and pleomorphic adenomas themselves. Primary myoepithelial tumors of the bone are exceedingly rare, and to our knowledge, HMGA2 rearrangements have not been previously reported in soft tissue or bone myoepithelial neoplasms. Through this report, we aim to enhance the existing literature on myoepithelial neoplasms, while highlighting the importance of recognizing primary bone myoepitheliomas and contributing to a broader understanding of the pathogenetic landscape of myoepithelial tumors across diverse tissue types.

ABSTRACTBackgroundSkip lesions in bone sarcoma are a poorly described entity. Reports on skip lesions in osteosarcoma and Ewing sarcoma suggest that whole bone MRI should be obtained to evaluate for additional tumor foci given the association with worse outcomes. However, there is limited evidence to support whole bone imaging in chondrosarcoma.MethodsBetween 1995 and 2022, 129 patients with long bone chondrosarcoma were evaluated at our institution. Lesions were located most commonly in the femur in 64 patients and the humerus in 54 patients. All imaging studies and pathology reports were reviewed to determine the presence of skip lesions, defined as an area of histology‐confirmed chondrosarcoma that was separated from the primary lesion by normal bone on pathology.ResultsWhole bone imaging was obtained during initial staging in 107 patients with two‐thirds of patients receiving MRI, CT, or bone scan. Five patients (3.9%) were found to have skip lesions in the same bone as the primary tumor. There were no transarticular skip lesions. Skip lesions were detected in three patients with low grade chondrosarcoma (4.6%) and two patients with high grade chondrosarcoma (3.2%). All lesions were within 2 cm of the primary tumor. All were visible on MRI and CT of the primary site and one was visible on plain radiographs. The presence of skip lesions did not alter the type of surgical treatment in any patients.ConclusionSkip lesions in long bone chondrosarcoma are rare. All skip lesions in this study were in close proximity to the primary tumor and the same grade as the main lesion. Our results suggest that advanced imaging of the whole bone may be of low utility for evaluating the presence of skip lesions. The clinical significance of skip lesions in chondrosarcoma remains unclear, however, their presence did not impact the treatment plan in this series.

AimsVenous tumour thrombus (VTT) is a rare finding in osteosarcoma. Despite the high rate of VTT in osteosarcoma of the pelvis, there are very few descriptions of VTT associated with extrapelvic primary osteosarcoma. We therefore sought to describe the prevalence and presenting features of VTT in osteosarcoma of both the pelvis and the limbs.MethodsRecords from a single institution were retrospectively reviewed for 308 patients with osteosarcoma of the pelvis or limb treated between January 2000 and December 2022. Primary lesions were located in an upper limb (n = 40), lower limb (n = 198), or pelvis (n = 70). Preoperative imaging and operative reports were reviewed to identify patients with thrombi in proximity to their primary lesion. Imaging and histopathology were used to determine presence of tumour within the thrombus.ResultsTumours abutted the blood vessels in 131 patients (43%) and encased the vessels in 30 (10%). Any form of venous thrombus was identified in 31 patients (10%). Overall, 21 of these thrombi were determined to be involved with the tumour based on imaging (n = 9) or histopathology (n = 12). The rate of VTT was 25% for pelvic osteosarcoma and 1.7% for limb osteosarcoma. The most common imaging features associated with histopathologically proven VTT were enhancement with contrast (n = 12; 100%), venous enlargement (n = 10; 83%), vessel encasement (n = 8; 66%), and visible intraluminal osteoid matrix (n = 6; 50%). Disease-specific survival (DSS) for patients with VTT was 95% at 12 months (95% CI 0.87 to 1.00), 50% at three years (95% CI 0.31 to 0.80), and 31% at five years (95% CI 0.14 to 0.71). VTT was associated with worse DSS (hazard ratio 2.3 (95% CI 1.11 to 4.84).ConclusionVTT is rare with osteosarcoma and occurs more commonly in the pelvis than the limbs. Imaging features suggestive of VTT include enhancement with contrast, venous dilation, and vessel encasement. VTT portends a worse prognosis for patients with osteosarcoma, with a similar survivability to metastatic disease.Cite this article: Bone Joint J 2024;106-B(8):865–870.

AbstractBackgroundCompared to other sarcomas, myxoid liposarcoma (ML) is known to be radiosensitive, with improved oncologic outcomes. Although these tumors “shrink” following radiotherapy, there is a paucity of data examining the degree of radiosensitivity and oncologic outcome. The purpose of the study was to evaluate pre‐ and postradiotherapy tumor volume to determine if size reduction impacts outcome.MethodsWe reviewed 62 patients with ML undergoing surgical resection combined with preoperative radiotherapy, with pre‐ and postradiotherapy MRI. This included 34 (55%) males, with a mean age of 47 ± 14 years. All tumors were deep to the fascia, and 12 (19%) patients had tumors with a >5% round‐cell component.ResultsThe mean volume reduction was 54% ± 29%. Compared to patients with >25% volume reduction, patients with reduction ≤25% had worse 10‐year disease specific survival (86% vs. 37%, p < 0.01), in addition to an increased risk of metastatic disease (HR 4.63, p < 0.01) and death due to disease (HR 4.52, p < 0.01).ConclusionLack of volume reduction is a risk factor for metastatic disease and subsequent death due to disease in patients with extremity ML treated with combined preoperative radiotherapy and surgery. This data could be used to stratify patients for adjuvant therapies and follow‐up intervals.

AbstractIntroductionSacral tumor resection is known for a high rate of complications. Sarcopenia has been found to be associated with wound complications; however, there is a paucity of data examining the impact of sarcopenia on the outcome of sacral tumor resection.MethodsForty‐eight patients (31 primary sarcomas, 17 locally recurrent carcinomas) undergoing sacrectomy were reviewed. Central sarcopenia was assessed by measuring the psoas:lumbar vertebra index (PLVI), with the 50th percentile (0.97) used to determine which patients were high (>0.97) versus low (<0.97).ResultsTwenty‐four (50%) patients had a high PLVI and 24 (50%) had a low PLVI (sarcopenic). There was no difference (p > 0.05) in the demographics of patients with or without sarcopenia. There was no difference in the incidence of postoperative wound complications (odds ratio [OR] = 1.0, p = 1.0) or deep infection (OR = 0.83, p = 1.0). Sarcopenia was not associated with death due to disease (hazard ratio [HR] = 2.04, p = 0.20) or metastatic disease (HR = 2.47, p = 0.17), but was associated with local recurrence (HR = 6.60, p = 0.01).ConclusionsCentral sarcopenia was not predictive of wound complications or infection following sacral tumor resection. Sarcopenia was, however, an independent risk factor for local tumor recurrence following sacrectomy and should be considered when counseling patients on the outcome of sacrectomy.

Aims . Fibrous dysplasia (FD) is a benign fibro-osseous neoplasm that most commonly arises in the ribs, femur, and craniofacial bones. We analyzed features of FD arising in the spine/short tubular/small bones of the hands/feet (STSBHF), specifically assessing for pattern of bone formation (conventional, complex/anastomosing, psammomatoid/cementum like), myxoid change, and presence of osteoclast-type giant cells. Materials and methods . A total of 1958 cases of FD were reviewed, of which 131 arose in the spine/STSBHF representing 2.5% of institutional and 10% of consultation cases, respectively. Eighty-six cases had material available for review. Anatomic sites included vertebrae ( n = 58, 67%), short tubular bones ( n = 20, 23%), and small bones of the hands/feet ( n = 8, 9%). The most common morphologic pattern of bone identified was conventional ( n = 77, 90%), followed by complex/anastomosing ( n = 22, 26%) and psammomatoid/cementum like ( n = 22, 26%). Eighteen cases (21%) had matrix-poor areas. Hypercellular areas were identified in 6 cases, 2 cases of which showed matrix-poor areas. Osteoclast-type giant cells were noted in 9 cases and myxoid change was present in 3 cases. Radiologic imaging studies available for 41 cases nearly all demonstrated features typical of FD, but the diagnosis was not predicted due to the unexpected location. Conclusions . FD arising in the spine/STSBHF is rare and frequently results in expert consultation. A significant number of cases exhibited less commonly recognized patterns of bone formation, and stromal changes including osteoclast-type giant cells, and matrix poor areas. Furthermore, imaging features in the STSBHF are often less specific. Awareness of the morphologic spectrum at these locations coupled with radiologic correlation should aid in accurate classification.

Abstract Purpose The teres minor is particularly important for activities that require external rotation in abduction in the settings of both rotator cuff tears and reverse shoulder arthroplasty. This study sought to assess the incidence of teres minor fatty infiltration in a large cohort of consecutive patients evaluated with shoulder MRI for shoulder pain and to identify all associated pathologies in an effort to determine the various potential etiologies of teres minor involvement. Methods A retrospective review of 7,376 non‐contrast shoulder MRI studies performed between 2010 and 2015 were specifically evaluated for teres minor fatty infiltration. Studies were reviewed by two fellowship trained musculoskeletal radiologists. Muscle atrophy was graded on a 3‐point scale according to Fuchs and Gerber. The remaining rotator cuff tendons and muscles, biceps tendon, labrum, and joint surfaces were assessed on MRI as well. Results In this series, 209 (2.8%) shoulders were noted to have fatty infiltration of the teres minor. The rate of isolated fatty infiltration of the teres minor was 0.4%. Concomitant deltoid muscle atrophy was common, and occurred in 68% of the shoulders with fatty infiltration of the teres minor. Tearing of the teres minor tendon was extremely rare. Conclusion Fatty infiltration of the teres minor can occur in isolation, be associated with deltoid muscle atrophy only, or occur in the setting of rotator cuff full tears. Thus, fatty infiltration of the teres minor may be related to a neurologic process or disuse. Further long term longitudinal studies are necessary to be elucidate the etiologies. Level of Evidence Level IV.