| Abstract|| |
Pulmonary carcinosarcoma is an aggressive rare malignant tumor comprising a mixture of carcinoma and sarcoma components containing differentiated mesenchymal elements, such as malignant cartilage, bone, and skeletal muscle. We report a case which presented with unusual clinical features and proved cryptic until death. At autopsy, it was a stage IV lung malignancy and histopathology revealed a carcinosarcoma comprising an adenocarcinoma and an osteosarcoma with metastasis to the heart, lymph nodes, and both adrenals. To our knowledge, this is the first case of this subtype with metastasis to the heart. The present case had an unusual clinical presentation and its elusive nature towards diagnosis despite dissemination is noteworthy and unique in the literature.
Keywords: Pulmonary carcinosarcoma, thromboembolism, metastasis heart
|How to cite this article:|
Kaur A, Falleiro J, Ghosh A K, Mani N S. Pulmonary carcinosarcoma masquerading as a cryptic disseminated malignancy. Indian J Pathol Microbiol 2009;52:517-9
|How to cite this URL:|
Kaur A, Falleiro J, Ghosh A K, Mani N S. Pulmonary carcinosarcoma masquerading as a cryptic disseminated malignancy. Indian J Pathol Microbiol [serial online] 2009 [cited 2013 May 24];52:517-9. Available from: http://www.ijpmonline.org/text.asp?2009/52/4/517/56146
| Introduction|| |
Carcinosarcoma is a rare malignant tumor of the lungs comprising approximately 0.3% of primary lung neoplasia.  We present a case of this malignancy in a 37-year-old male, who proved cryptic till death. The clinical presentation was unusual, relentlessly progressive with a short time span towards a fatal outcome.
| Case Report|| |
A 37-year-old male presented with breathlessness and discomfort in chest accompanied by palpitations for one day. His hemogram revealed a nutrophilic lukocytosis (TLC-14,500/cu mm). A computerized tomographic angiogram of the lungs revealed evidence of bilateral pulmonary embolism. He was placed on thrombolytic therapy. A pleural tap of a small right sided pleural effusion revealed an exudative fluid with lymphocyte predominance. Five days after admission, an echo revealed a pericardial effusion and a tail of a thrombus in right atrium. A therapeutic pericardiocentesis was done for recurring cardiac tamponade. Thereafter, he developed features of deep vein thrombosis of both legs. An inferior vena cava (IVC) filter was placed to prevent a shower to the lungs. In spite of high doses of anticoagulants, the thrombosis proved to be relentless, involving the deep veins (upto IVC filter), the lungs and the heart. A suspicion of prothrombotic genetic abnormality (Protein C, Protein S and factor V Leiden, homocysteine levels) and an occult cancer was kept in mind; however, hematological assays, pleural, pericardial fluid cytology and radiological imaging continued to be negative for the same. The patient's condition deteriorated thereafter and 44 days after admission, the patient succumbed to his illness. A clinical diagnosis of pneumonia with sepsis and pulmonary embolism was given at death.
A complete autopsy was carried out six hours after death. An irregular dark grey colored lesion was seen in the lower region of the left upper lobe at the periphery; 2 mm from the pleural surface [Figure 1]. The lesion was 3 x 2 cm 2 in dimension with an ill-defined peripheral border. It appeared to be extending into the surrounding tissue as a diffuse congestive solidification of the entire lung. The cut surface of both the lungs elsewhere was rough, solid and granular. Thromboemboli were seen in medium sized and small arteries ([Figure 1] inset). Histopathological examination from sections taken from the lesion seen in the left upper lobe, revealed an infiltrating neoplasm with a biphasic pattern comprising of predominant adenocarcinoma along with sarcomatous stromal elements. The latter comprised of pleomorphic cells exhibiting a malignant cytomorphology laying down malignant osteiod with bone formation [Figure 2]. Mitoses were brisk and atypical in these areas. Hence, there was a coexisting adenocarcinoma and an osteosarcoma in the same lesion. The adenocarcinoma component was seen involving both lungs diffusely with predominant lepidic spread along the alveolar walls. Lymphangectatic pattern of invasion was also a prominent feature. The osteosarcoma component comprised only about twenty percent of the lesion. The biphasic pattern with heterologous elements (adenocarcinoma and osteosarcoma) coexisting within the same tumor provided the basis for the diagnosis of the tumor as a carcinosarcoma as per the WHO classification (2004). 
The pericardium was seen plastered onto the myocardium. A diffuse solid white band with a varying thickness of 0.5-3 mm was seen at the interface of the myocardium and pericardium. Mural thrombi in both the ventricles and the left auricle were present. A large relatively fresh thrombus extending up to the hilum of the right lung was seen in the main pulmonary artery.
Complete occlusion by thrombi of the IVC filter and deep veins of both legs was present. Hilar and paraortic lymph nodes were enlarged. Microscopy confirmed metastasis of the adenocarcinoma component into the pericardium with focal areas of infiltration into the myocardium and the interstitium of the heart, paraortic lymph nodes and both adrenals.
Histochemistry and immunohistochemistry
Representative sections of the neoplasm were periodic acid-Schiff stain positive and diastase resistant in sections from areas conforming to the adenocarcinoma. Immunohistochemistry done on representative sections from the paraffin embedded tissue with antibodies to pancytokeratin (+++), carcinoembryonic antigen (++), epithelial membrane antigen (+++), and vimentin (+++) (DAKO, UK, in dilutions of 1:100, 1:200, 1:50 and 1:100, respectively) revealed positive reactions. TTF-1 (++) and CK7 (++) (DAKO, UK,1:200, 1:100) were found to be positive in the adenocarcinomatous areas [Figure 3].
| Discussion|| |
Pulmonary carcinosarcomas are known to occur in elderly and middle aged smokers. The male to female ratio is seven and the mean and median age is 65 years.  Clinically, two subtypes have been described; central endobronchial tumors which present earlier and peripheral relatively indolent tumors. The prognosis of the peripheral subtype as in the present case is poor. ,
The metastatic lesions have been described as only carcinomatous in 50%, only sarcomatous in 40% and as both components in 10% lesions.  In the present case, all the metastasizing lesions (lymph nodes, heart and adrenals) showed evidence of adenocarcinoma component only.
The association of cancer with venous thromboembolism is well known and has been attributed to a number of mechanisms including activation of clotting by tumor cells, vessel-wall injury and stasis.  Studies to suggest venous thromboembolism as a predictor of subsequent diagnosis of cancer and further stressing on extensive investigations to search for an elusive cancer have been controversial some favoring  and some not in favor of such an outlook. 
The present case is unusual and significant to record in a number of ways. The patient was a young previously healthy individual, a nonsmoker presenting with pulmonary thromboembolism progressing to widespread thromboembolic phenomenomenon. The lepidic spread of this tumor along the alveolar walls, in all probability, facilitated the tacit cryptic dissemination in the lungs. This pattern of spread, akin to that described in bronchioloalveolar carcinomas of the lung appears to be elusive on imaging. It mimics an interstitial pneumonitis on imaging and hence evades the diagnosis of a disseminating malignancy.
Dissemination to the heart from this subtype of carcinosarcoma of the lungs and a clinical presentation with extensive inexorable systemic thromboembolism is unique in this case and to our knowledge the first such report. To facilitate early diagnostic detection, we reiterate the association of thromboembolism with occult cancer and intensive search for the same, especially in the lungs.
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Department of Pathology, Military Hospital (Cardiothoracic Center), Pune Camp, Maharashtra-411040
[Figure 1], [Figure 2], [Figure 3]