Dr. Pepe’s Diploma Casebook: CASE 123 – SOLVED!

Dear Friends,

Today I am presenting radiographs of a 68-year-old man with pain in the left ankle for the last two months. I will show additional images on Wednesday.

Diagnosis:

1. Periosteal sarcoma
2. Osteomyelitis
3. Soft tissue sarcoma
4. None of the above

Check the images below, leave your thoughts in the comments section, and come back on Friday for the answer.

Dear Friends, presenting today MRI images of the left ankle. Hope they help with the diagnosis!

Click here for the answer

Findings: Lateral view of the ankle shows an ill-defined anterior cortical lytic lesion (A, arrow), seen as a hypodense area in the AP view (B, circle). Bone scan confirms a single bone lesion (C, arrow).

MR images show an anterior cortical mass (D and E, arrows), suspected to be a bone sarcoma. Tru-cut biopsy findings diagnosed metastatic adenocarcinoma. The chest radiograph showed a left paramediastinal pulmonary mass (F, arrow). Biopsy confirmed adenocarcinoma of the lung.

Final diagnosis: tibial cortical metastasis from lung carcinoma

Most of us are familiar with the common manifestations of lung carcinoma in the chest radiograph. Today I would like to address an unusual form of presentation: extrapulmonary metastasis as the first manifestation of the disease. This presentation form occurs in about 1% of patients. It should be kept in mind to avoid misdiagnoses and treatment delays.
In this chapter I would like to review the most common sites of metastasis as the initial manifestation of a lung tumor.

About half the metastases from undiagnosed lung cancer occur in the skeleton. Remember that most bone malignancies in adults are metastatic lesions rather than primary bone tumors, with a ratio of about 20 to 1.

Pain is the most common symptom in skeletal metastasis. When it is the initial symptom of unknown lung cancer, in most cases (80%) the spine is the affected site (Fig. 1). The remaining 20% involve the femur, pelvis or humerus (Fig. 2). Metastasis to the distal extremities is highly suspect of a lung primary (Fig. 3).

Fig. 1. 89-year-old man with increasing back pain for the last 4 months. Radiographs on admission show a lytic lesion in the anterior aspect of L3 (B, circle), confirmed on sagittal CT (C, circle). 

The chest radiograph at this time shows a left parahilar mass (D, arrow). Enhanced axial CT confirms an irregular left lung mass. Diagnosis: carcinoma of the lung with metastasis to the lumbar spine.

Fig. 2. 58-year-old man with hip pain for several weeks. AP view of the pelvis shows destruction of the right pubic branch (A, arrow). PA chest radiograph shows a nodule (asymptomatic) in LUL (B, arrow). Biopsy confirmed a primary lung tumor with metastasis to the pelvis.
Fig. 3. 80-year-old man with a painful, swollen first toe. Radiograph shows a soft tissue mass with destruction of the first phalanx (A, arrow), confirmed with CT (B, circle). The Tru-cut biopsy findings diagnosed a metastatic lesion. PA chest radiograph shows an RUL mass (C, arrow), later confirmed to be a squamous cell carcinoma (Case courtesy of Jordi Andreu, MD).

Hypertrophic osteoarthropathy is a paraneoplastic syndrome associated with lung cancer, characterized by pain and extensive periostitis of the hands and long bones. Its discovery should prompt a chest radiograph to investigate a chest malignancy (Fig. 4).

Fig. 4. 68-year-old man with pain in both hands. Radiograph of the forearm shows extensive wavy periostitis (A, arrows), suspicious of hypertrophic osteoarthropathy. PA radiograph depicts a mass in the right lung (B, arrow), confirmed with CT (insert, arrow): Squamous-cell carcinoma.

The brain is a common target for lung metastasis, but it is rarely the first site of symptoms (Figs. 5 and 6). It has been reported that brain metastasis is the first manifestation of lung cancer in 2% of patients. The brain was the only metastatic site in 75% of these patients.

Fig. 5. A 64-year-old woman presented with neurological symptoms. MRI of the head depicted a large mass in the left occipital lobe (A, arrow). Chest radiography discovered a mass (asymptomatic) in the RUL (B, arrow), confirmed with CT (insert, arrow).
Diagnosis: lung adenocarcinoma with a single brain metastasis
Fig. 6. 50-year-old man who presented with neurological symptoms and a brain tumor. Pre-op chest radiographs discovered a pulmonary mass hidden in the right posterior costophrenic sinus (A and B, arrows).

Coronal and sagittal CT confirm the presence of a large mass (C and D, arrows). Final diagnosis: lung carcinoma with metastasis to the brain.

Metastasis to the skeletal muscle occurs in less than 1.5% of lung cancers, usually in advanced phases of the disease. Occasionally, the metastatic lesions cause the first symptoms and should not be confused with a soft tissue sarcoma, which has similar clinical and radiologic features (Fig. 7).

Fig. 7. A 58-year-old man, previously well, developed a painful mass in the left gastrocnemius in the last two months. Ultrasound confirmed the mass (A, arrow), which was isointense with muscle in MR T1W images (B, arrow). A necrotic center and peripheral enhancement were seen after gadolinium injection. The diagnoses offered were abscess vs. myonecrosis vs. atypical tumor. Biopsy came back as metastatic disease.

PA chest radiograph taken after the biopsy shows a double contour of the aortic knob (D, arrow), secondary to a barely visible lung mass in the anterior clear space in the lateral view (E, arrow). Enhanced axial CT confirmed the mass (insert, arrow).
Diagnosis: adenocarcinoma

Extrathoracic metastatic lymph nodes can simulate soft tissue masses and may be interpreted initially as primary soft tissue tumors (Fig. 8).

Fig. 8. 64-year-old physician treated successfully for bladder carcinoma two years ago. Now a soft-tissue mass is detected in the left groin. US shows a probable enlarged lymph node (A, arrows). Pre-op radiograph prior to removal of the mass depicts a right pulmonary opacity B, white arrow) and enlarged hilar and mediastinal lymph nodes (B, red arrows).

Enhanced coronal CT shows a peripheral mass (C, white arrow) and hilar and mediastinal nodes (C, red arrows). Axial CT of the groin confirms an enlarged lymph node (D, arrow). Final diagnosis: adenocarcinoma of the lung with mediastinal metastases and a single metastatic lymph node in the left groin.

Pancreatic metastasis from lung carcinoma is not uncommon and usually found in advanced cases. Pancreatitis is an unusual form of initial presentation provoked by pancreatic metastasis, which is said to occur in less than 0.1% of patients (Fig. 8).

Fig. 8. 49-year-old woman admitted with acute abdominal pain. Enhanced abdominal CT shows classic signs of pancreatitis (A, arrow). A cephalad CT slice of the lung depicts a right hilar mass (B, arrow) with infiltration of the middle lobe. Biopsy confirmed an unsuspected carcinoma of the lung as the probable cause of pancreatitis.


Follow Dr. Pepe’s advice:

1. About half of initially-appearing lung metastases occur in the skeleton.

2. Malignant-appearing bone lesions in the hands or feet should prompt a CXR.

3. Brain metastasis as the initial presentation occurs in about 2% of lung cancer cases.

4. Do not confuse muscle metastasis with soft tissue sarcoma.

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