VANISHING PALPABLE MASS IN A YOUNG FEMALE PATIENT TIFFANY SHICK, BS, NEEL D. GUPTA, MD, JEREMY B. NGUYEN, MD FACR HISTORY
IMAGING FINDINGS Figure 1. Frontal and lateral radiographs of the right forearm in a skeletally immature patient demonstrate subtle osseous exostosis extending from the ulnar aspect of the radial diaphysis away from the radiocarpal articulation. Figure 2. Axial T1 MRI demonstrates osseous exostosis contiguous with medullary cavity of the radius with subtle suspected cartilaginous cap. Skin marker is noted superficial to the exostosis. Figure 3. Axial T2 fat saturated MRI demonstrates minor non- mass like soft tissue edema surrounding the osseous exostosis. Additional subtle marrow type edema signal involving the osseous exostosis. Figure 4. Sagittal T1 MRI demonstrates osseous exostosis contiguous with medullary cavity of the radius with subtle suspected cartilaginous cap. Figure 5. Axial T1 MRI obtained in 2012 demonstrates interval significant decreased osseous exostosis contiguous with medullary cavity of the radius with subtle suspected cartilaginous cap. Decreased mass effect on surrounding soft tissues at the level of the “regressed” osseous exostosis. Skin marker is noted superficial to the exostosis. Figure 6. Axial T2 MRI obtained in 2012 demonstrates interval significant decreased osseous exostosis contiguous with medullary cavity of the radius with subtle suspected cartilaginous cap. Decreased mass effect on surrounding soft tissues at the level of the “regressed” osseous exostosis. Skin marker is noted superficial to the exostosis. Figures 7, 8 and 9. Axial T1 MRI obtained in 2012 demonstrates significant decreased osseous exostosis contiguous with medullary cavity of the radius with subtle suspected cartilaginous cap (red arrow in Figure 7). Coursing extensor digitorum anomalous tendon slip noted near osseous exostosis (red arrows in Figure 8 and 9). Skin marker is noted superficial to the exostosis.
their cartilage-capped projections from long bones. They are slow growing lesions within immature skeletal tissue and most often do not progress in size beyond puberty (3). Many of these lesions are solitary, however roughly 15% of patients with an osteochondroma have been diagnosed with multiple tumors in the context of a rare hereditary condition called multiple hereditary exostoses (MHE) (2). While the lesions themselves are largely benign, there are potential causes for removal such as fractures, proximal structure deformity, and malignant transformation. If the patient is asymptomatic, treatment for the lesion is typically taken through a conservative approach with interval observation. Surgical treatment is more common in patients with MHE. As was shown noted in this case, an osteochondroma may be intimately associated with a tendon and may elicit pain during movement due to mechanical friction. The tendon may slide and be injured over the bony lesion (3). Additionally pathologic fractures may occur of an osteochondroma and cause significant pain. When considering potential treatment for patients with an osteochondroma, it is important to note existing cases of spontaneous regression. Although there are just a few reports of this process in the literature, available limited studies suggest that most cases of spontaneous regression have been noted in males aged 5 to 11 years old. Mechanism of regression is not fully understood; however, the causes are likely multifactorial. One proposed remodeling pathway involves regression following fracture while another model suggests bone remodeling. In such cases of tumor disappearance, complete resolution took several years (5). Reduction of bone appeared greatest during adolescence, correlating with timeline of epiphyseal arrest in development (4). While the statistical prevalence of regressing osteochondroma may remain unclear due to largely asymptomatic presentation, clinicians should take caution in considering surgical intervention versus conservative observation. In the presented case, surgery was not recommended for the patient due to the lack of significant symptoms and unnecessary surgical risks that could arise from operation. Following three years of conservative observational treatment, imaging demonstrated spontaneous regression of the patient’s bone tumor. REFERENCES 1. Galanis, N., Delniotis, I., Noussios, G., Katsourakis, A., Kitridis, D., Leidinger, B., & Givissis, P. (2020). Osteochondroma of the distal tibia in an 8‐year‐old child: Do we need to excise a benign tumor? Clinical Case Reports , 8(12), 3599–3600. https://doi.org/10.1002/ccr3.3321 2. Heyworth, P. B., & Rashid, M. (2018). Regression of a solitary osteochondroma of the distal humerus in a toddler following trauma. Radiology Case Reports , 14(2), 187–189. https://doi. org/10.1016/j.radcr.2018.10.006
14-year-old female presenting with painful palpable mass along the right radial shaft. Initial imaging was obtained in 2009 with follow-up imaging conducted in 2012.
Initial Imaging: 2009
Figure 1
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Radiographs of the Right Forearm
Axial T1 MRI
Axial T2 Fat Sat MRI
Follow Up Imaging: 2012
DIFFERENTIAL DIAGNOSIS 1. Parosteal Osteosarcoma 2. Osteochondroma 3. Nonossifying Fibroma (NOF) 4. Osteoid Osteoma FINAL DIAGNOSIS Regressing “Vanishing” Osteochondroma DISCUSSION
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Sagittal T1 MRI
Axial T1 MRI
Axial T2 MRI
We present a case of a young female patient presenting with a painful palpable abnormality of the distal right upper extremity. Three years following initial imaging, various signs of spontaneous tumor regression are evident. Osteochondromas are benign osseous surface lesions that are often asymptomatic, thus incidental diagnosis is not uncommon. Osteochondromas are the most common benign bone tumors and are defined by
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3. Tepelenis, K., Papathanakos, G., Kitsouli, A., Troupis, T.,
Axial T1 MRI
Axial T1 MRI
Axial T1 MRI
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J LA MED SOC | VOL 176 | FALL 2024
J LA MED SOC | VOL 176 | FALL 2024
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