Chest wall tumors reflect a wide range of the various musculoskeletal diseases. Their infrequency in this unique location generates a diagnostic and therapeutic challenge to the thoracic surgeon. More than half the malignant tumors of the chest wall represent either metastatic lesions from distant organs (i.e., carcinoma or sarcoma) or invasion from contiguous structures such as the breast, lung, pleura, or mediastinum.¹ Primary malignant neoplasms include tumors that arise from soft, cartilaginous, or bony tissues. The most common pathology is sarcoma and, less frequently, solitary plasmacytoma or lymphoma. In many series, the number of patients reported is small because of the rarity of primary chest wall malignant tumors; thus the data on these cases are limited. From these data it can be concluded that approximately 45% of primary malignant chest wall tumors arise from soft tissue sarcomas and 55% appear in cartilaginous or bony tissue.²

The soft tissue chest wall tumor commonly presents as an enlarging mass without pain. Conversely, patients with bone tumors most often have pain as their initial complaint secondary to periosteal damage or expansion. Rapidly expanding lesions more often produce pain and favor a malignant diagnosis. The character of the pain is a persistent, dull aching sensation that is likely related to stretching of the pericostal sheath.

Constitutional complaints such as fever and malaise may accompany Ewing sarcoma. Rarely, a benign bony lesion such as osteomyelitis or eosinophilic granuloma may present as a painful bony mass with fever and malaise. Other clinical signs and symptoms produced by chest wall and sternal malignancies are related to invasion or pressure effects that the tumor exerts on adjacent structures.

Chest wall masses can be divided into three main categories: malignant, benign, and nonneoplastic. More than half of all chest wall tumors represent metastases from different sites or local invasion of adjacent tumors. Primary chest wall tumors are relatively uncommon and represent only 1% to 2% of all primary neoplasms. Table 134-1 classifies the malignant neoplasms of the chest wall.

Benign tumors comprise approximately half the primary neoplasms of the chest wall. The most common benign neoplasms in the chest wall are osteochondroma and chondroma. Osteochondroma is the most common benign rib neoplasm and accounts for nearly 50% of this group. It is usually asymptomatic and does not mandate removal. Chondromas usually occur anteriorly at the costochondral junction. The chondroma commonly presents as a slowly enlarging mass that may range from slightly painful to not painful at all. It is impossible to differentiate a chondroma from a chondrosarcoma on clinical and radiographic examination, and microscopic differentiation can be extremely difficult. Therefore, wide surgical excision is recommended for these tumors.

Nonneoplastic conditions include inflammations and cysts. Fibrous dysplasia is a cystic, nonneoplastic lesion characterized by fibrous replacement of the medullary cavity of the rib. It usually manifests as a slowly enlarging, nonpainful mass in the posterolateral rib cage. Excision is not indicated unless it enlarges and becomes painful.

The evaluation of patients with chest wall masses should include a careful history and physical examination, followed by plain film chest x-ray. Particular attention should be paid when there is a history of previous malignancies or if there are recognized risk factors for soft tissue and bone sarcomas. These factors include previous radiation therapy, exposure to chemicals (e.g., vinyl chloride and arsenic), immunodeficiency, prior injury (e.g., scars and burns), chronic tissue irritation (e.g., foreign-body implants), neurofibromatosis, Paget disease, bone infarcts, and genetic cancer syndromes (e.g., hereditary retinoblastoma, Li–Fraumeni syndrome, and Gardner syndrome). In most patients, however, no specific etiology can be identified.

CT Scanning and MRI

CT scanning and MRI play complementary roles in the evaluation of chest wall masses. CT scanning is faster and less expensive and more accurately demonstrates cortical bone distraction from masses arising in the ribs. MRI, on the other hand, is better for depicting infiltration of bone marrow and evaluating the extent of intraspinal and soft tissue involvement. The choice of technique, CT scanning versus MRI, often depends on the clinical question being addressed. CT scanning of the chest is necessary to rule out metastatic disease.

Molecular Imaging

The exact role of ¹⁸F-fluorodeoxyglucose PET/CT (18F-FDG PET/CT) scanning in the diagnosis and management of chest wall malignancies has not been fully determined. Substantial evidence supports its use in soft tissue and bone sarcoma. Fugl⊘ et al.³ retrospectively reviewed FDG PET/CT in 89 patients with high-grade bone and soft tissue sarcoma. They found high sensitivity, specificity, and accuracy, 95%, 96%, and 95%, respectively, for detection of lymph node and distant metastases. They also found that the maximum standardized uptake value (SUVmax) of the primary tumor was a strong predictor of survival. A high SUVmax indicated a poor prognosis, a lower value a better prognosis. Nishiyama et al.⁴ also found the SUV max value in FDG PET/CT to be an independent predictor of event-free survival and overall survival in 42 patients with chest wall sarcoma. 18F-FDG PET/CT scanning might also be useful in patient management as a tool for biopsy guidance, whole-body staging, therapeutic response assessment, and evaluation of residual mass lesions after treatment. 18F-FDG PET/CT scanning may aid tumor grading but offers inadequate discrimination between low-grade tumors and benign lesions.

Tissue Diagnosis

While obtaining tissue for diagnosis, there are several pitfalls to keep in mind. The skin incision or the Tru-Cut needle tract must not jeopardize subsequent skin flaps. Hematoma must be avoided because it may propel sarcoma cells into and along soft tissue planes. The biopsy must be adequate for pathologic study. Necrotic tissue, hematoma, or inflammatory tissue may be present within the biopsy rather than tumor tissue, and therefore, if there is any question about the adequacy of the tissue specimen, a frozen section to confirm the cancerous tissue should be performed.

Core Needle Biopsy

Percutaneous core needle biopsy was found to be effective and safe for the diagnosis of musculoskeletal masses.⁵ It can be performed either by palpation or using image-guided procedures, that is, CT scan, fluoroscopy, or ultrasonography. Welker et al.⁵ found that CT-guided biopsy permitted 88% of the patients with suspected sarcomas to undergo a single needle biopsy procedure before the initiation of definitive treatment. Only 7.4% of the masses in their study required open biopsy. Besides being cost-effective, core needle biopsy limits the size of the biopsy tract that must be removed at the time of definitive wide or radical excision. If neoadjuvant therapy is planned, the treatment can be given immediately without waiting for wound healing. It should be emphasized that while evaluating a patient with previous malignancy for suspected chest wall metastasis, fine-needle aspiration should be sufficient for making a diagnosis.

Open Biopsy

Open biopsy should be employed when the needle biopsy is not diagnostic, or for tumors with unusual histologic patterns, when it is important to know whether these patterns are present throughout the whole lesion or confined to small areas of the tumor. In these circumstances, open biopsy will be more informative. Open biopsy also appears to be superior for the diagnosis of cystic bone lesions. These lesions contain substantial amounts of fluid, blood, and necrotic material that are not diagnostic. A biopsy specimen from the wall of the lesion is therefore needed.

Open biopsy can be either excisional or incisional, but any incisional biopsy site must be planned to permit complete excision of its scar with the primary tumor at a subsequent surgical resection. It is accepted that for tumors smaller than 5 cm, excisional biopsy should be performed with at least 1-cm margins, while incisional biopsy is recommended for tumors greater than 5 cm, taking into consideration future definitive resection. In cases of a primary malignant tumor diagnosed by excisional biopsy, the patient should usually undergo reoperation for radical resection and wider margins.

Chondrosarcoma

Chondrosarcoma is the most common primary malignant bone tumor of the chest wall. It is more common in males and in the age group of 30 to 60 years. It usually presents on the anterior chest wall, arising from the costochondral arches or sternum. It may occur as the result of malignant degeneration of a benign chondroma. Both chondrosarcomas and benign chondromas present as painful, slow-growing, hard, fixed, and nontender anterior chest wall masses. Radiologic features of both tumors may be indistinguishable; therefore, a histologic diagnosis is required to assess malignancy. Chondrosarcoma has the appearance of a large expanding mass containing chondroid-type calcifications accompanied by a significant soft tissue component that causes distraction of the bone (Fig. 134-1). Current therapy for chondrosarcoma requires adequate surgical excision with a margin of at least 4 cm. Chemotherapy is ineffective, and radiation therapy is used only for patients with tumors that are either not amenable to surgical resection or have positive resection margins. In the Mayo Clinic series,⁶ the overall survival rate at 5 years was 92%. The recurrence rate for patients with adequate surgical margins was 10%, compared with 75% in patients with inadequate surgical margins. The 5-year survival rate for patients with adequate surgical margins was 100%, compared with 50% in patients with inadequate surgical margins. Inadequate surgical margins of resection were associated with a significantly decreased overall survival and a higher chance of local recurrence.

Osteosarcoma

Osteosarcoma is much less common than chondrosarcoma among primary bony chest wall malignancies. Although osteosarcoma represents the most common primary malignant tumor arising in bone, only 3% arise from the chest wall (Fig. 134-2). Osteosarcomas occur in a bimodal age distribution. Adolescents and young adults are affected most commonly, with a smaller subgroup of patients developing osteosarcoma after age 40. It commonly presents as a rapidly enlarging, painful mass. In older patients, secondary osteosarcoma may develop in preexisting diseases of the bone, such as Paget disease, bone infarction, sites of previous radiation, and so forth. Metastatic disease (lung mostly) is present in one-third of patients at initial presentation, and over two-thirds of patients will develop metastases at some point. For this reason, perioperative chemotherapy is standard treatment, with improved 5-year survival of up to 50% for extremity osteosarcoma. Given that primary osteosarcoma of the chest wall is such a rare tumor, it is permissible to extrapolate the survival benefit of chemotherapy from extremity osteosarcoma, with the exception that tumors presenting in diverse sites may respond differently. Radiotherapy is largely ineffective in treating osteosarcoma.