般瑞医疗科技

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Clinical History

A 17-year-old Nigerian boy attended the emergency department with a 9-month history of pain in his right leg. Physical examination revealed localized swelling and a palpable mass.

Imaging Findings

Plain radiography and magnetic resonance imaging (MRI) were performed, and a biopsy specimen was taken. The patient was diagnosed with non-Hodgkin lymphoma.
Imaging studies revealed an osseous lesion with a destructive pattern involving the medullary and cortical bone of the proximal tibial metadiaphysis and associated soft-tissue masses.
The radiograph showed an osteolytic lesion with aggressive features, such as cortical breakthrough, pathologic fracture, soft-tissue masses, and interrupted periosteal reaction (Codman triangle) (Figure 1). Cortical destruction was complete in the proximal portion of the tumour and partial with a permeative pattern in the distal portion. MRI and, more particularly, contrast-enhanced imaging revealed permeative cortical bone with a linear pattern of intracortical high signal intensity (SI) and no disturbance of cortical integrity (Figure 2).
MRI showed marked extension of the tumour to the soft tissues and into the knee joint. On the T2-WI sequence, the SI of the intraosseous tumour was lower than that of subcutaneous fat.

Discussion

Primary bone lymphoma (PBL) is one of the rarest primary malignant tumours of bone, and most cases involve non-Hodgkin lymphoma. Lymphoma in bone with no evidence of lymphomatous disease elsewhere for at least 6 months after diagnosis confirms the diagnosis of PBL (1).
The clinical presentation of PBL is insidious bone pain that can persist for months, sometimes with systemic symptoms. Other signs include local swelling and a palpable mass in long bones, particularly the femur, tibia, pelvis, and humerus. Although PBL presents in several age groups, it is more frequent in patients aged over 30 years.
Plain radiography findings of PBL are variable and non-specific, and the differential diagnosis includes a wide range of lesions (osteomyelitis and malignant tumors such as osteosarcoma and Ewing sarcoma). Despite the lack of specificity in the radiographic pattern, a diagnosis of PBL should be considered when a solitary lytic tumour near the end of a long bone has a permeative or moth-eaten destructive pattern accompanied by an aggressive periosteal reaction (2). The differences in treatment and improved survival rates with PBL compared with other primary malignant tumours of bone, stress the importance of recognizing PBL (2).
On other imaging studies (CT, MRI, and Tc 99m radionuclide imaging), PBL does not have a specific pattern. The literature on the MRI features of PBL focuses mainly on the appearance of cortical bone, soft-tissue abnormalities, and SI characteristics (3). Involvement of cortical bone is subdivided into complete, focal, and permeative cortical destruction and cortical thickening. The MRI pattern of permeative cortical destruction showing multiple linear foci of intermediate or high SI penetrating the cortex is characteristic of bone lymphoma, but not specific, and it is observed in other small round cell tumors and metabolic and inflammatory processes, including hyperparathyroidism and osteomyelitis.
Low SI on T2-WI sequences is reported as a feature of bone lymphoma owing to a high content of fibrous tissue.
The pattern of large soft tissue masses without extensive cortical destruction is common in PBL.
In summary, although radiographic and MRI findings may suggest a diagnosis of bone lymphoma, it is not possible to differentiate lymphoma from other processes based solely on imaging. Therefore, biopsy is necessary. MRI, and particularly Gd-enhanced sequences, can determine the response to chemotherapy and/or radiation therapy, which in turn has a direct impact on individual patient care.

Differential Diagnosis List

Primary non-Hodgkin lymphoma of tibia

Osteomyelitis

Osteosarcoma

Ewing sarcoma

Final Diagnosis

Primary non-Hodgkin lymphoma of tibia

Liscense

Figures

Figure 1.Anteroposterior and lateral right leg radiograph at presentation.

Figure 2. MRI before and after intravenous injection of gadopentetate dimeglumine.

Medical Imaging Analysis Report

I. Imaging Findings

The patient is a 17-year-old male with localized bone destruction in the right lower leg (proximal or mid tibia), along with a soft tissue mass. On X-ray images, the bone exhibits a “moth-eaten” or diffuse pattern of destruction, and there may be focal cortical destruction or irregular cortical thickening, as well as periosteal reaction. On MRI, cortical involvement is noted, with a mass extending into the surrounding soft tissues, resulting in varying degrees of soft tissue swelling. On T2-weighted images, the lesion often appears as low or intermediate signal, with a pronounced soft tissue component.

II. Possible Diagnoses

Primary Bone Lymphoma (PBL): Although more commonly diagnosed in individuals over 30 years old, it can also occur in adolescents. Radiologically, it may present as a solitary lytic lesion with a moth-eaten appearance and a sizable soft tissue mass. On MRI, cortical invasion and formation of a large soft tissue mass are common, with T2 signals often appearing relatively low, which is consistent with the imaging features in this case.
Osteosarcoma: Common in adolescents. X-ray findings often show bone destruction along with new bone formation (e.g., tumor osteoid), a Codman triangle, and sunburst periosteal reaction. However, the soft tissue lesion and low T2 signal observed in this case are not entirely consistent with the typical bony proliferation and calcification associated with osteosarcoma.
Ewing Sarcoma: Mostly affects children and adolescents, often exhibiting a lytic lesion in the diaphysis or metaphysis, with an “onion skin” type periosteal reaction. However, Ewing Sarcoma is more commonly associated with high signal on T2-weighted MRI. In this case, the lesion primarily shows low signal on T2 and differs somewhat in the extent of lesion involvement and cortical disruption.
Osteomyelitis: Chronic osteomyelitis can present with a moth-eaten bone appearance, but typically includes more obvious signs of infection (e.g., persistent fever, leukocytosis or other abnormal lab findings). Additionally, an abscess or sinus tract may be visible on MRI. In this case, the clinical course is prolonged (9 months), and systemic infection markers may be atypical, so osteomyelitis remains a consideration but is less likely.

III. Final Diagnosis

Based on the patient’s persistent bone pain over nine months, the moth-eaten osteolytic destruction seen on X-ray and MRI, the large soft tissue mass, and the relatively low T2 signal, the most likely diagnosis is Primary Bone Lymphoma (PBL). However, imaging alone is insufficient to definitively distinguish it from other malignant bone tumors or chronic infections. Therefore, histopathological biopsy and relevant hematological tests are required for confirmation.

IV. Treatment Plan and Rehabilitation

1. Treatment Strategy

Chemotherapy and Radiotherapy: Primary bone lymphoma typically requires systemic chemotherapy (commonly CHOP or similar regimens) combined with local radiotherapy to shrink and eradicate the lesion.
Surgical Intervention: For patients with severe bone destruction or high risk of pathological fracture, surgical fixation or reconstruction may be considered; however, tumor control with chemotherapy and radiotherapy is generally prioritized.
Pharmacotherapy: Depending on the patient’s overall condition and the tumor’s cellular characteristics, individualized immunotherapy or targeted therapy may be considered (this is determined after further pathological typing).

2. Rehabilitation and Exercise Prescription

During the acute phase or early treatment stage, protect the affected limb with protective weight-bearing or partial weight-bearing to prevent pathological fracture.
After chemotherapy or radiotherapy, gradually begin low-intensity aerobic and resistance training. Specifics are as follows:
- Frequency: 2-3 times per week.
- Intensity: Start at a low level, such as walking at a pace that induces slight shortness of breath but still allows conversation.
- Time: 15-20 minutes per session initially, gradually increasing the duration as tolerated.
- Type: Options include walking, wall-sits, or lower-extremity resistance exercises with resistance bands.
- Progression: As the condition improves and bone stability increases, slowly increase weight-bearing intensity and training duration in a stepwise manner.
- Volume, Pattern: Divide exercises into 2-3 sets each session, with 1-2 minute rest intervals between sets. Focus on monitoring pain and fatigue levels.
If bone fragility or fracture risk is high, use braces or crutches, and emphasize balance training and safety precautions.
Regular follow-up is recommended, adjusting the exercise plan according to imaging findings and clinical symptoms over time.

Disclaimer: The above content is a reference analysis based on currently provided information and cannot replace an in-person diagnosis or professional medical advice. In case of any doubts or special changes in the condition, please consult a certified specialist promptly.

Human Doctor Final Diagnosis

Primary non-Hodgkin lymphoma of tibia

AI Doctor