Journal of Clinical and Diagnostic Research. 2018 Dec, Vol-12(12): ED13-ED15 13 13 DOI: 10.7860/JCDR/2018/37941.12379 Case Report Pathology Section Osseous Metaplasia in Adenocarcinoma CASE REPORT CASE 1 A 48-year-old male presented with acute onset abdominal distension, pain and obstipation for five days. X-ray abdomen showed multiple air-fluid levels suggestive of intestinal obstruction. A provisional diagnosis of acute intestinal obstruction secondary to an underlying Tumor was made. Routine investigations were normal except for serum Carcinoembryonic Antigen (CEA) levels, that were mildly raised (3.19 ng/mL). The patient underwent emergency exploratory laparotomy in which a large fungating mass was seen completely obstructing sigmoid colon along with paracolic lymphadenopathy. The patient underwent left-sided hemicolectomy with an end colostomy. On gross examination, resected specimen, 30.5×4.0 cm in size, showed an ulceroproliferative firm to hard growth measuring 6.0×5.0×4.0 cm [Table/Fig-1]. Microscopic examination showed a Tumor in the sigmoid colon arranged in a complex glandular and focal cribriform pattern, exhibiting moderate nuclear anaplasia. The background showed abundant extracellular mucin. Laminated bony trabeculae of varying thickness rimmed by cuboidal to polygonal uninucleate bland looking osteoblasts were diffusely seen in the stroma in close proximity to the Tumor [Table/Fig-2]. The bony trabeculae, however, did not enclose any marrow elements. Focal areas of calcification were also evident in the necrotic areas of the Tumor suggestive of dystrophic calcification. Histopathological diagnosis of moderately differentiated adenocarcinoma, mucin- secreting type with OM was made. Eleven lymph nodes resected from the specimen were free of Tumor and did not show any evidence of ossification. PHIZA AGGARWAL 1 , RPS PUNIA 2 , ROBIN KAUSHIK 3 , MANVEEN KAUR 4 , DEEPAK AGGARWAL 5 Keywords: Heterotopic ossification, Malignancy, Tumor ABSTRACT Osseous Metaplasia (OM) or heterotopic ossification is a rare phenomenon with unknown aetiology that is characterised by the formation of mature bone elements in the stroma of different tumors. Awareness of this condition is important to avoid diagnostic confusion with carcinosarcoma and local bone invasions that have different lines of treatment and prognosis. Here, authors report two cases of heterotopic ossification in adenocarcinoma of sigmoid colon and lung and provide salient features that could help to detect the condition. [Table/Fig-1]: (Case 1): The resected specimen showing Tumor (black arrow) in sigmoid colon. [Table/Fig-2]: (Case 1): Section shows glandular Tumor with osseous metaplasia (black arrow) in a mucinous background (H&E, x400). CASE 2 A 42-year-old male presented with cough, chest pain and dyspnea for 2-3 months and haemoptysis for the last two weeks. X-ray chest PA view presented an ill-defined opacity in the right hilar and parahilar region along with cardiomegaly [Table/Fig-3]. Contrast Enhanced Computed Tomography (CECT) thorax showed a small mass in the right bronchus intermedius along with sub-segmental collapse of the superior segment of right lower lobe [Table/Fig-4]. Considering a middle-aged and non-smoker, a provisional diagnosis of subacute infection, like tuberculosis, was made. Patient underwent flexible bronchoscopy which showed an endo-bronchial growth in the right bronchus intermedius. Endo-bronchial biopsy showed a Tumor arising from the overlying dysplastic bronchial mucosa and comprising of malignant cells arranged in sheets and focal glandular pattern. Interspersed within the Tumor was seen an irregularly deposited osteoid lined by bland osteoblasts [Table/Fig-5]. The bony trabeculae were lying in close proximity to the Tumor without any evidence of Tumor invasion. The histopathological diagnosis of adenocarcinoma lung with heterotopic ossification was made. The patient underwent systemic chemotherapy which resulted in a partial decrease in the size of the Tumor.