Right-sided pain and discomfort of a few months duration.
The patient complained of pain and discomfort on the right side of the chest of a few months' duration. PA and lateral plain films of the chest were performed. These showed an ill-defined calcific lesion projecting over the right sixth rib. the lesion appeared to be in close contact with the rib on the lateral view. A diagnosis of osteochondroma of the rib was made. CT of the chest was performed for further evaluation and this confirmed the diagnosis of osteochondroma, with a well-delineated cartilaginous cap being demonstrated.
The patient returned after 3 months with a sudden increase in pain. Plain chest radiographs revealed a small pneumothorax on the right side, in addition to the osteochondroma.
The patient agreed to undergo surgery and pathology confirmed the diagnosis.
Osteochondroma (osteocartilaginous exostosis) is one of the most common neoplasm occuring in the skeleton(although strictly speaking it is not a neoplasm). The cartilage capped subperiosteal bone projection accounts for 20-50% of benign bone tumours. They occur most frequently in the first two decades of life with a male to female ratio of 1.5:1.They occur most often in long bones, especially the distal femur and proximal tibia, with 40% of the tumours occurring around the knee.
Osteochondromas of the ribs are rare and nearly always arise at or near the anterior end of the rib. They cause expansion or deformity of the rib with calcification of the cartilaginous cap. They can be mistaken for an area of pneumonia or a solitary pulmonary mass. CT allows a more definitive evaulation, especially of the cap.
Osteochondromas are most likely caused either by a congenital defect or by trauma of the perichondrium which results in the herniation of a fragment of the epiphyseal growth plate through the periosteal bone. They can either be sessile or pedunculated (stalk-like), with a slender pedicle directed away from the joint, and appear in the juxta-epiphyseal location. They occur only in bones that develop from cartilage (endochondral ossification). They have been reported to occur as a result of radiation therapy in children. There is normally no further growth of the exostosis after epiphyseal fusion.
Clinically, they present with pain due to mechanical irritation or a painless mass. A fracture can occur through the stalk of the lesion. Occasionally they are an incidental finding.
Hereditary multiple osteochondromatosis (diaphyseal aclasis) is an autosomal dominant condition with lesions (both sessile and pedunculated) occurring on different bones or on the same bone. Nearly 50% of these patients have a rib lesion.
Plain films are normally sufficient to diagnose the condition. Sessile lesions cover a wide area and can cause metaphyseal widening. The cartilaginous cap displays irregular areas of calcification. CT is helpful in determining whether the marrow and cortices of the lesion are continuous with the bone. The thickness of the cartilage cap is best delineated on MRI. The cartilage cap ranges from 1mm to 6mm in thickness; over 2cm of cartilage or renewed growth is a sign of possible malignant transformation.
The differential diagnosis includes hereditary multiple osteochondromatosis (diaphyseal aclasis). The differential diagnosis of rib lesions includes enchondroma, osteoblastoma, osteoid osteoma, chondroblastoma and haemoangioma.
Complications may occur; osteochondromas in areas other than the knee are more likely to undergo malignant transformation. Secondary chondrosarcoma occurs in 0.5-1% of patients with a solitary osteochondroma. Chondrosarcoma transformation is more common in the hereditary form.Dynamic Gd-enhanced MR can be used to differentiate benign from low grade malignant cartilaginous tumor.Both early and exponential enhancement being predictors of malignancy.Gd-enhanced MR can further help in tumor mapping in case a biopsy is indicated. Spontaneous haemothorax or pneumothorax (as in this case) have been reported in rib lesions, as have fractures.
Pathologically, on gross examination, an osteochondroma is an irregular bony mass with a bluish grey cap of cartilage. Opaque yellow cartilage has calcification within the matrix. The base of the lesion has a rim of cortical bone and central cancellous bone. Microscopically, the lesion shows endochondral ossification on the basal surface of hyaline cartilage. The cartilage is more disorganised than normal, the thickness of the cap is usually 1-3mm, and greater thickness may imply malignant transformation.
No treatment is necessary for asymptomatic osteochondromas. If the lesion is causing pain or neurological symptoms due to compression it should be excised at the base. The prognosis of a solitary exostosis is excellent. In this case, the patient had surgery as she developed spontaneous pneumothorax and the diagnosis was confirmed at pathology.
Osteochondroma of the rib
The patient is a 22-year-old female who has complained of right-sided chest pain for several months. A chest X-ray (frontal and lateral views) indicates a protruding bony lesion near the anterior segment of the right rib, with the margin appearing continuous with the rib. In the CT axial view, calcifications can be seen on the surface of the mass, which appears protrusive and includes a cartilaginous density. Some compression or localized change is observed in the neighboring chest wall structures. The lesion is continuous with the normal bone cortex and bone marrow signal, suggesting it may originate from the surface of the rib. A small pneumothorax sign is noted at the apex of the lung, suggesting a history of spontaneous pneumothorax.
Considering the patient’s young age (22-year-old female), clinical symptoms (persistent right-sided chest discomfort and localized pain), imaging findings (protrusion with a cartilaginous cap that is continuous with the rib cortex and marrow), and confirmation via postoperative pathological diagnosis, the most likely diagnosis is:
Rib Osteochondroma
In cases of asymptomatic or mildly symptomatic osteochondroma, a watch-and-wait follow-up approach is commonly taken. Since the patient in this case suffered from spontaneous pneumothorax, and experienced localized pain and discomfort, surgical resection was performed with a good prognosis.
Postoperative Rehabilitation and Exercise Prescription Recommendations:
Throughout the rehabilitation process, adhere to the FITT-VP principles (Frequency, Intensity, Time, Type, Progression, and Personalization), adjusting according to the patient’s recovery status and subjective symptoms.
This report is an interpretive analysis based on the available imaging and information. It does not replace an in-person consultation or a professional physician’s diagnosis and treatment plan. Patients should maintain regular communication with their specialist. If any questions or new symptoms arise, seek immediate medical attention.
Osteochondroma of the rib
