Chest wall mass
The patient was admitted with swelling and deformity on the right side of the chest wall. On PA chest radiograph and magnetic resonance imaging (MRI), a large expansile mass originating from the posterior part of the right 8th rib was demonstrated. The lesion was largely isointense with areas of hypointensity to skeletal muscle on T1-weighted images and heterogeneously hyperintense on T2-weighted images. After administration of gadolinium DTPA, patchy central and peripheral rim enhancement was noted. No cystic or hemorrhagic changes were detected.
Fibrous dysplasia (FD) is one of the most frequently encountered anomalies of benign skeletal disorder. It may involve a single bone (monostotic fibrous dysplasia) or many bones (polyostotic fibrous dysplasia). This idiopathic benign condition is a slowly progressive disorder where normal medullary space of the affected bone is replaced by fibroosseous tissue. Fibrous stroma is a myxofibrous tissue of low vascularity, while the bone trabeculae are composed of woven bone with little layering. It usually presents in the first two decades. Patients with small, monostotic lesions may be asymptomatic, identified incidentally on radiologic studies. When present, symptoms are nonspecific, include pain, swelling, tenderness and stress or pathologic fracture. In monostotic form, the ribs (%28), proximal femurs (%23) and craniofacial bones (%20) are most commonly affected. In polyostotic fibrous dysplasia, the spectrum of involvement varies from two bones to more than %75 of the skeleton and lesions are more extensive (ie, larger and longer). Radiologically, fibrous dysplasia of the rib is a slowly progressive, well-marginated osteolytic lesion whose epicenter is medullary. Endosteal scalloping of the adjacent cortex may be irregular and thin. The margins are sharp and often sclerotic. Occasionally bone expansion may be asymmetric toward the side of the thoracic cavity. FD may extend throughout a long segment of rib, approximately 20 cm in length. The matrix of the lesion may be radiolucent or demonstrate peripheral trabeculations and appear loculated, or it may demonstrate variable degrees of mineralization with a faint amorphous homogeneous increase in density, so called ground-glass appearance. The amount of woven bone and the extent which is minarelized, will ultimately determine the radiographic density of the lesion. MR imaging is useful in accurately defining the full extent of the lesion. The signal intensity varies from low to high on T2-weighted images but typically is heterogeneous and low in areas of lesion involvement on T1-weighted images. Signal intensities on T1 and T2-weighted images and the degree of contrast enhancement on T1-weighted images were depended on the amount of bony trabeculae, cellularity, collagen tissue and vascularity of the mass. Malignant transformation may be suspected due to a change in the radiological appearance of the lesion. The most common malignant transformation reveals osteosarcoma, followed by fibrosarcoma and chondrosarcoma, giant cell sarcoma. The differential diagnosis in monostotic fibrous dysplasia may include simple bone cyst, osteoma, ossifying fibroma, osteoblastoma, giant cell tumor, menengioma, osteosarcoma and chondrosarcoma. Polyostotic fibrous dysplasia must be differentiated from hyperparathyroidism, Paget's disease, neurofibromatosis and tuberous sclerosis. The diagnosis of fibrous dysplasia is based on a combination of clinical, radiological and pathological findings.
Fibrous Dysplasia
On the patient’s chest X-ray, there is a relatively clear bony lesion near the left chest wall and ribs. The lesion has a fairly well-defined boundary with mixed-density bone in some areas, showing a slight “ground-glass” appearance. The cortical bone may appear thinned or slightly indented (with thinning and mild irregularity of the inner cortex), but overall maintains a relatively intact bony edge.
MRI in the transverse and coronal planes shows a lesion in the left chest wall with heterogeneous signal intensities. On T1-weighted images, the lesion mainly appears as low or isointense, while on T2-weighted images, some areas show high signal intensity, some show low or mixed signal, and overall there is heterogeneous enhancement. The lesion’s boundary is relatively clear, with expansile growth and no significant signs of adjacent soft tissue infiltration.
Considering the patient’s age (27 years), clinical symptoms (chest wall mass, possible discomfort or occasional pain), imaging features (relatively well-defined boundary, ground-glass-like bony changes, heterogeneous MRI signals but relatively localized), as well as the common locations and characteristics of fibrous dysplasia, the most likely diagnosis in this case is monostotic fibrous dysplasia (single-lesion fibrous dysplasia).
If there is still any diagnostic uncertainty, further pathological evaluation through biopsy or surgical specimen examination can be considered to confirm the histological characteristics.
Treatment Strategy:
1) Observation and Regular Follow-ups: If the lesion is small and symptoms are not significant, conservative management with periodic imaging follow-ups to monitor progression can be chosen.
2) Surgical Intervention: If there is significant pain, instability of bone structure, increased risk of pathological fracture, or local functional impairment, surgical treatment may be considered, including curettage of the lesion, bone grafting, or resection.
3) Medication and Supportive Care: Pain may be managed with standard analgesics. For patients with low bone density, consultation with a specialist regarding anti-osteoporotic medications can be considered.
Rehabilitation and Exercise Prescription (following the FITT-VP principle):
In rehabilitation, attention should be paid to:
Disclaimer:
This report is based on the imaging and limited clinical information provided by the patient. It offers a reference-based medical analysis and does not replace in-person consultation with a qualified physician. If you have further questions or if the condition changes, please seek medical attention promptly.
Fibrous Dysplasia
