Sarcomatoid carcinoma: Description, Causes and Risk Factors:
Sarcomatoid carcinoma is an extremely rare biphasic tumor characterized by a combination of malignant epithelial and mesenchymal cells. Limited data on sarcomatoid carcinoma showed that most cases occurred with advanced local disease and metastasis, and paraneoplastic syndromes were rare. We present the case of a 63-year-old man with lung sarcomatoid carcinoma associated with jejunum metastasis and leukocytosis, and its clinical, macroscopic, and histopathological features. This case emphasizes the importance of recognizing paraneoplastic syndromes and metastasis of sarcomatoid carcinoma at diagnosis.
Although sarcomatoid carcinoma has been reported in many sites of the body such as the bladder, colon, uterus, ovary, breast, and lung, few pathologists have the opportunity to study very many of them. Fishback designated sarcomatoid carcinomas as pleomorphic (spindle/giant cell) carcinomas of the lung because both spindle and giant cell components often are found in the same tumors. The World Health Organization (WHO) histological classification of lung tumors or carcinomas with pleomorphic, sarcomatoid, or sarcomatous elements includes: 1) carcinomas with spindle and/or giant cells (pleomorphic carcinoma, spindle cell carcinoma, and giant cell carcinoma), 2) carcinosarcoma, 3) pulmonary blastoma, and 4) others. Spindle and giant cell carcinoma and carcinosarcoma comprise only 0.4% and 0.1% of all lung malignancies, respectively.
There is no specific clinical presentation and typical symptoms include chest pain, cough, hemoptysis, dyspnea, fever, and weight loss. Limited data on sarcomatoid carcinoma showed that most cases were associated with advanced local disease at diagnosis. However, metastasis and paraneoplastic syndromes are rarely seen in the clinic. We present the case of a 63-year-old man with lung sarcomatoid carcinoma with jejunal metastasis and leukocytosis, as well as its clinical, macroscopic, and histopathological features.
Sarcomatoid carcinomas can arise centrally or peripherally, but most commonly, they present as solitary, peripheral masses with a predilection for the upper lobes, similar to other smoking-related non-small cell carcinomas of the lung. Tumors are large, ranging from 2 cm to 18 cm and often invade the chest wall. Tumor consistency is described as soft and fleshy to firm, hard, or rubbery. Cut surfaces vary from white-grey to tan-yellow, frequently show areas of hemorrhage and necrosis, and occasionally demonstrate cavitation.
In summary, the sarcomatoid carcinomas of the lung are a subset of poorly differentiated non-small cell lung cancers. Throughout the decades, the classification and concepts pertaining to the histogenesis of these neoplasms have been controversial. The histologic criteria for the 5 sarcomatoid carcinoma subtypes established by the World Health Organization is straightforward and can readily be applied by light microscopy, knowledge of the histologic criteria and most common considerations in the differential diagnosis will aid in selection of appropriate immunohistochemical studies. Coupling the pathologic findings with the clinical history and distribution of the disease on imaging should help avoid misdiagnosis.
These are generally considered highly aggressive tumors, which may metastasis to unusual sites. Others have found no difference in prognosis from non-sarcomatoid carcinomas. There may be a higher rate of gastrointestinal tract involvement than for other non-small cell carcinomas. Giant cells constituting less than 10% of the tumor may be found in squamous cell carcinomas and adenocarcinomas and do not worsen the prognosis.
The typical symptoms of sarcomatoid carcinoma are the same as for most lung cancers and include chest pain, cough, hemoptysis, dyspnea, fever, and weight loss. Paraneoplastic syndromes such as dermatomyositis and Trousseau’s syndrome were reported in uterine sarcomatoid carcinoma and ovarian carcinosarcoma.However, no paraneoplastic syndromes were reported in lung sarcomatoid carcinoma although they occurred with about 15-20% of small cell lung cancers and 5-8% of non-small cell lung cancers.
The striking morphologic variability of the sarcomatoid carcinomas has important implications for diagnosis. On small biopsies, the diagnosis of a member of this group may be suspected but is often difficult to substantiate, particularly when adenocarcinoma, squamous cell carcinoma, or large cell carcinoma, and sarcoma elements are absent. Conventional carcinoma and sarcoma components in these tumors are often inconspicuous; thus, in resection specimens, adequate sampling is essential and should include at least one section per centimeter of maximum tumor diameter. This approach will generate a considerable number of histologic slides for review because many of the sarcomatoid carcinomas are quite large.
Employing multiple keratin antibodies, the epithelial lineage of the spindle and giant cell components of pleomorphic carcinoma can often be demonstrated. AE1/3, CAM 5.2, CK18, and CK7 are positive more frequently than epithelial membrane antigen, carcinoembryonic antigen (CEA), CD15, and Ber-EP4. Positive epithelial markers are not required for diagnosis if components of adenocarcinoma, squamous cell carcinoma, or large cell carcinoma are present. Spindle cell carcinoma that is negative for the epithelial markers is difficult to separate from sarcoma. In this situation, it is helpful to remember that although spindle cell carcinoma is rare, it is more common than primary sarcoma of the lung.TTF-1 is useful in supporting the pulmonary origin of these tumors and is more sensitive than surfactant protein-A.Keratin antibodies may highlight the epithelial component of carcinosarcoma but typically diffusely stain the epithelial component of pulmonary blastoma. Muscle markers and S100 protein stain rhabdomyosarcoma and chondrosarcoma, respectively, when present in either carcinosarcoma or pulmonary blastoma.
The histologic heterogeneity of the sarcomatoid carcinomas generates a broad spectrum of considerations for the differential diagnosis. However, on a practical basis, the most commonly encountered lesions in the differential diagnosis are relatively few and, for simplicity, can be organized into 4 groups: carcinoma with a desmoplastic stroma, differential diagnosis within the subtypes of sarcomatoid carcinomas, malignant mesothelioma, and primary or metastatic sarcoma.
The prognosis of this tumor remains poor, even in patients with resectable disease. The overall 5-year cancer-specific survival rate after cystectomy in our study population was only 20.3%, suggesting a high risk of early dissemination. Recently, cystoprostatectomy with lymphadenectomy plus various combinations of neoadjuvant or adjuvant chemotherapy and/or radiotherapy has been advocated by some authors. However, the outcomes have been variable and inconsistent. While some authors reported promising results with ovarian or sarcoma-type chemotherapy regimens, others reported a poor outcomes regardless of the type of treatment.
Most of patients were treated with cancer directed surgery (CDS), 35 (15.8%) of patients received radiation therapy combined with cancer-directed surgery. One patient received radiation before and after surgery; 34 patients received radiation after surgery. Among the patients who received cancer directed surgery, 119 (53.9%) patients underwent transurethral resection for bladder tumor only and 79 (35.7%) patients underwent partial or radical cystectomy. In 3.2% of cases, no surgical or radiation therapy was given after the diagnosis was established.
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