Ann Thorac Surg 2003;78:709-711
© 2003 The Society of Thoracic Surgeons
Case report
Lung cancer and skeletal muscle metastases
Angelo Di Giorgio, MDa*,
Paolo Sammartino, MDa,
Carlo Luigi Cardini, MDa,
Monir Al Mansour, MDa,
Fabio Accarpio, MDa,
Simone Sibio, MDa,
Marisa Di Seri, MDb
a Dipartimento di Chirurgia "Pietro Valdoni", Università "La Sapienza" Rome, Italy
b Dipartimento di Medicina Sperimentale e Patologia, Università "La Sapienza," Rome, Italy
Accepted for publication June 30, 2003.
* Address reprint requests to Dr Di Giorgio, Università degli Studi di Roma "La Sapienza," Dipartimento di Chirurgia "Pietro Valdoni" Policlinico Umberto I, Via Lancisi 2-00161, Rome, Italy
e-mail: angelo.digiorgio{at}uniroma1.it
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Abstract
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Skeletal muscle metastases from lung cancer are rare, and the optimal treatment strategy is unknown. Three cases of skeletal muscle metastases from lung cancer are described. In 2 patients surgical biopsy of muscle swelling disclosed the presence of the lung tumor; the first patient underwent lung resection to remove the primary lesion, the second was not operable because of the metastatic extension of the disease. In the third patient muscle metastasis was observed and excised after lung resection. Adenocarcinoma, squamous cell, and small cell carcinoma were the histologic types diagnosed. Various regimens of radiotherapy and chemotherapy were adopted. Survival times were 3, 6, and 30 months.
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Introduction
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Skeletal muscle metastases from lung cancer are rare events and even more rarely are they the only clinical manifestation of disease. In most cases muscle metastases become apparent after the primary lung lesion has been diagnosed and the tumor has already metastasized through the lymphatic system or blood to other sites. The rarity in the development of skeletal muscle metastases from lung or extrapulmonary epithelial carcinomas has engendered various theories on the physiologic mechanisms underlying the poor receptiveness of the muscular tissue to the formation of secondary lesions. We describe 3 cases of skeletal muscle metastases from lung cancer in patients who had distinct clinical presentations, management, and outcomes.
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Case reports
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Patient 1
A 39-year-old man, a heavy smoker, underwent excision of a mass of about 2 cm in diameter involving the extensor muscles of the forearm. The surgical specimen showed a skeletal muscle metastasis from adenocarcinoma. Blood chemical tests gave normal findings. A total body computed tomographic (TBCT) scan disclosed an opacity of about 1.5 cm in diameter in the upper lobe of the right lung. Fiberoptic bronchoscopic examination yielded negative findings.
A wedge pulmonary resection was performed in the right upper lobe; the histologic diagnosis of the resected specimen was primary adenocarcinoma of the lung according to immunostain for CK7 epithelial keratin. The patient received three cycles of adjuvant chemotherapy followed by local radiation therapy to the forearm. Four months later the patient was readmitted to our department complaining of right chest pain and dyspnea. A TBCT scan showed an expansive extrapleural lesion on the right side of the chest wall; other regions appeared uninvolved. A right posterolateral re-thoracotomy at the fifth intercostal space showed a mass involving the intercostal muscles at the level of the fourth, fifth, sixth, and seventh ribs without abutting the parietal pleura or infiltrating the lung parenchyma. The chest-wall segment containing the involved costal segments was resected. The histologic finding was moderately differentiated adenocarcinoma infiltrating the intercostal soft tissues with costal bone tissue erosion without involvement of the parietal pleura. The diagnosis was a muscle hematogenous metastasis from adenocarcinoma.
Despite regimens of radiotherapy and chemotherapy, 3 months later a TBCT showed new swellings in the left and right major dorsal muscles and in the left deltoid muscle. The patient underwent a palliative surgical excision of the deltoid swelling to relieve pain and functional impotence. The histologic examination confirmed the diagnosis of skeletal muscle metastasis from adenocarcinoma. Despite further chemotherapy the disease progressed and metastases developed in the long muscles of the dorsum. Eight months later, a TBCT scan showed further masses in the nuchal and back muscles without evidence of metastases in other areas (Fig 1). Four months later, 30 months after the first operation, the patient died of a myocardial infarction.
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Fig 1. Case 1: Computed tomography scan showing roundish metastases involving the long muscles of the dorsum (arrows).
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Patient 2
A 57-year-old man, a heavy smoker, was admitted to our department with a lung lesion of about 6 cm in diameter in the right upper lobe. Blood chemical tests, bronchoscopic examination, TBCT scan, and bone scintigraphy showed no abnormalities. Fine needle aspirations raised the suspicion of a non–small cell lung cancer (NSCLC). The patient underwent right upper lobectomy. The histologic diagnosis was of poorly differentiated squamous cell carcinoma (pT2N0M0).
Four months after surgery a painful swelling of about 4 cm in diameter developed in the left major dorsal muscle. The patient underwent surgical resection of the lesion; the mass involved only the muscular plane without evident contact with the ribs or the parietal pleura. The histologic diagnosis was muscle metastasis from NSCLC. One month later a TBCT scan disclosed a brain metastasis. Six months after the primary operation, disease progression led to the patient's death.
Patient 3
A 37-year-old man, a nonsmoker, was admitted to our department after a 1-month history of persistent cough, fever, weakness, and weight loss. Physical examination disclosed the presence of painful swelling (1.5 cm in diameter), in the biceps muscle of the left arm. A computed tomography (CT) scan showed a lesion of about 2 cm in diameter in the upper lobe of the left lung and large lymph-node mediastinal swellings. The CT scan also showed a 5-cm nonhomogeneous mass within the long muscles of the dorsum in the left paravertebral site. Bronchoscopy showed normal appearances. The excisional biopsy of the muscular lesion yielded diagnosis of muscular metastasis from small cell lung cancer. Despite chemotherapy the disease progressed and 2 months later a new CT scan showed the presence of contralateral pulmonary and bilateral adrenal metastases; other metastatic lesions were visible in the long muscles of the back. The patient died 3 months after diagnosis.
Comment
Despite being highly vascular, skeletal muscle is usually resistant to hematogenous metastases from epithelial neoplasms. The reported incidence is less than 1% in clinical series [1–3]. The likelihood of skeletal muscle disease, including metastases, being diagnosed at autopsy relates directly to number of muscle groups examined. Analyzing a relevant number of muscles in cadavers of patients who died of cancer, Pearson [3] detected skeletal muscle metastases in 16% of the cases. Skeletal metastases from primary lung cancer are rare events and the literature includes few reports [2, 4, 5]. The 3 cases we have described were observed in a case series of 3,000 patients treated for lung cancer in our surgical department since 1970. The rarity of skeletal muscle metastases may depend on the various mechanisms linked to blood flow, metabolism, and high tissue pressure [3, 6]. Histologically, skeletal muscle metastases may appear as nodules or infiltrates. Evidence suggesting a hematogenous origin of skeletal muscle metastases comes from the presence of neoplastic vascular emboli [3]. The typical clinical manifestations are local pain, increased muscle tone and the development of a swelling.
In the literature 14 cases of lung cancer patients with skeletal muscle metastases were available for analysis. With one exception, all the patients were men; the mean age was 55.4 years (range 31 to 79 years). In the first of our 3 patients and in 6 of the 14 reported cases skeletal muscle metastases were the sole initial clinical manifestation of the lung neoplasm. The most frequent histologic type in the reported cases was squamous cell carcinoma; no cases of large cell tumors were found in the literature or in our series. The muscle groups most often involved were those of the arm and the shoulder, lumbar spine, and thighs. In the literature series 11 patients had metastatic disease also in sites other than muscles. In 4 of the 14 reported cases, the muscular metastasis was excised and in 3 surgery disclosed the presence of a lung tumor. In another 3 cases in which the muscle metastasis was the initial sign of the disease, the muscular mass was not excised. In 3 cases the lung was resected before the muscular metastasis developed. Eleven patients in the literature underwent radiation or chemotherapy, or both. In all our patients some muscular metastases were excised.
Regardless of surgical or medical therapy the presence of skeletal muscle metastases portends poor survival. Only 2 cases (1 of our series) survived 30 months. The first of our 3 patients is the only case so far described in whom a muscle metastasis disclosed a primary lung cancer that could be resected and whose tumor involved progressively only skeletal muscles.
The onset of muscle pain resistant to medical therapy in patients with lung cancer should raise a suspicion of skeletal muscle metastases and a thorough diagnostic workup is necessary, including TBCT, magnetic resonance imaging scanning, ultrasound, and fine needle biopsy. Optimal strategy is unknown and the presence of skeletal muscle metastases does not modify the regimens of chemotherapy and radiation therapy according to the histologic type of the primary lung tumor and disease staging. Drug-resistant pain from muscle metastases is the main indication for their surgical resection according to their number, site, and dimensions and independently of histologic type. Should skeletal muscle metastases disclose the presence of NSCLC, if the primary tumor can be resected and neither lymphatic nor hematogenous spread are detectable, then aggressive surgical management comprising resection of muscle metastases could be indicated.
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References
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- Ménard O., Parache R.M. Les metastases musculaires des cancers. Ann Med Intern (Paris) 1991;142:423-428.[Medline]
- Pearson C.M. Incidence and type of pathologic alterations observed in muscle in a routine autopsy survey. Neurology 1959;9:757-766.
- Sridhar K.S., Rao R.K., Kunhardt B. Skeletal muscle metastases from lung cancer. Cancer 1987;59:1530-1534.[Medline]
- Mc Keown P.P., Conant P., Auerbach L.E. Squamous cell carcinoma of the lung: an unusual metastasis to pectoralis muscle. Ann Thorac Surg 1996;61:1525-1526.[Abstract/Free Full Text]
- Nicolson G.L. Organ preference of metastasis. Prog Clin Biol Res 1986;212:25-40.[Medline]
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Abstract
Introduction
