| Abstract|| |
Histiocytic sarcoma is a rare malignant neoplasm that demonstrates mature histiocytic traits as characterized by immunohistochemistry. We report a case of extranodal histiocytic sarcoma (ENHS) of colon in a 56-year-old man presenting with gastrointestinal symptoms. Radiological findings were indicative of lymphoma or diffuse metastatic disease in colon. Histopathology of colectomy specimen was suggestive of ENHS, and immunohistochemical studies confirmed the uncommon diagnosis. The patient refused further therapy and succumbed to systemic complications of metastatic disease within a month of diagnosis. There have only been seven previous reports in world literature of ENHS involving large intestine.
Keywords: CD68, colon, histiocytic sarcoma
|How to cite this article:|
Mitra S, Jhunjhunwala A, Mukherjee P. Extranodal histiocytic sarcoma mimicking colorectal lymphoma: Case report and review of literature. Indian J Pathol Microbiol 2019;62:467-9
|How to cite this URL:|
Mitra S, Jhunjhunwala A, Mukherjee P. Extranodal histiocytic sarcoma mimicking colorectal lymphoma: Case report and review of literature. Indian J Pathol Microbiol [serial online] 2019 [cited 2020 Feb 21];62:467-9. Available from: http://www.ijpmonline.org/text.asp?2019/62/3/467/263482
| Introduction|| |
Histiocytic sarcoma (HS) is a malignant proliferation of cells showing similar morphologic and immunophenotypic features to mature tissue histiocytes. The atypical neoplastic cells can closely resemble high-grade lymphomas, and radiological findings are often nonspecific. It is an extremely rare neoplasm occurring in lymph nodes and extranodal sites such as skin, soft tissue, and intestinal tract. HS often presents at an advanced clinical stage with aggressive clinical course, poor response to chemotherapy, and a high mortality rate.,, We report here a case of HS of colon with typical morphological and immunophenotypic features.
| Case Report|| |
A 56-year-old male was admitted to the hospital with complaints of cough, hemoptysis, pain in the abdomen, occasional hematemesis, melena, and bleeding from rectum for the past 20 days. There was no history of fever or weight loss. The patient was a smoker and a known case of Type 2 diabetes mellitus and hypertension.
The patient had previously undergone bronchoscopy and colonoscopy that had revealed a right lung mass and a colonic growth. The earlier endoscopic biopsy from colonic growth had been reported elsewhere as malignant neoplasm, suggestive of non-Hodgkin's lymphoma.
On admission to this hospital, initial clinical examination and routine hematological and biochemical investigations were unremarkable except for anemia (72 g/L hemoglobin) and markedly elevated C-reactive protein (339.2 mg/L).
Ultrasonographic findings were unremarkable, chest roentgenogram showed a mass lesion in the right lower lobe of lung, and contrast-enhanced computed tomography (CECT) of the chest showed a multilobulated mass lesion in the right lower lobe of lung with few reactive mediastinal lymph nodes.
CECT abdomen showed multilevel heterogeneously enhancing colonic mass with multiple soft-tissue masses in the abdomen. There was a concentric focal narrowing of rectum by soft-tissue thickening along with retroperitoneal lymphadenopathy, bilateral adrenal lesions mainly necrotic, and cystitis. The radiological impression was suggestive of lymphoma or metastatic disease.
CT-guided trucut biopsy from soft-tissue mass in the right lumbar region was performed. Repeat colonoscopy revealed a large vascular left colonic tumor with active bleeding, due to which biopsy could not be attempted, along with a rectal polyp mass which was identified as an inflammatory polyp on biopsy.
Due to persistent blood loss from rectum, the patient underwent exploratory laparotomy, and total colectomy with ileostomy was performed. Gross examination of the resected colectomy specimen showed a dilated segment of colon with few markedly enlarged lymph nodes in paracolic fat. On opening the specimen, a large polypoidal growth was found with hemorrhagic and necrotic cut surface. Microscopic examination of both the colonic growth and the trucut biopsy from the right soft tissue at lumber region showed sheets of large pleomorphic cells with abundant eosinophilic cytoplasm, resembling cells of anaplastic large-cell lymphoma (ALCL) or diffuse large B-cell lymphoma (DLBCL). Cells were epithelioid-like, with abundant pale eosinophilic cytoplasm, oval to irregular nuclei, vesicular chromatin, and prominent nucleoli. Mitotic figures were noted. Few multinucleated giant cells and hemophagocytosis were also evident [Figure 1] and [Figure 2].
|Figure 1: (a) CECT scan abdomen showing multilevel heterogeneously enhancing colonic mass. (b) Colonoscopic image showing large vascular colonic tumor. (c) Dilated segment of colon with large tumor, as seen on gross examination. (d) Sheets of large pleomorphic cells in submucosa (H and E, ×100)|
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|Figure 2: (a–c) Sheets of large pleomorphic cells with abundant eosinophilic cytoplasm (a: H and E, ×40; b, c: H and E, ×100). (d) Inflammatory cell infiltrate in tumor (H and E, ×100)|
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Immunohistochemistry showed tumor cells weakly to moderately positive for CD 45, strongly positive for Vimentin and CD68, and focally positive for EMA, S-100, and CD30. Cells were immunonegative for CD 3, CD 20, CD34, CK, HMB-45, and Melan-A [Figure 3]. Final histopathological diagnosis was HS of colon with metastases.
|Figure 3: (a) Neoplastic cells positive for CD45 (immunoperoxidase, ×100). (b) Neoplastic cells positive for CD68; inset – tumor giant cell (immunoperoxidase, ×100). (c-f) Neoplastic cells immunonegative for CK (c), CD20 (d), Melan-A (e), and CD34 (f) (immunoperoxidase, ×100). (g) Neoplastic cells focally positive for S-100 (immunoperoxidase, ×100). (h) Neoplastic cells positive for Vimentin (immunoperoxidase, ×100)|
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| Discussion|| |
HSs are rare malignant neoplasms of presumed hematopoietic origin showing morphologic and immunophenotypic evidence of histiocytic differentiation. They are more prevalent in middle-aged and elderly patients and share some distinctive features including frequent extranodal presentation and poor prognosis. There is no apparent gender difference.,
The most common primary sites of involvement include lymph nodes and extranodal sites such as skin, gastrointestinal tract, central nervous system, spleen, bone marrow, and thyroid. Search of world literature revealed seven previous reports of extranodal histiocytic sarcoma (ENHS) involving the large intestine [Table 1].,,,
HS is diagnosed on the basis of characteristic histological features usually large epithelioid cells with abundant pale eosinophilic cytoplasm and multiple areas of mitosis, with supportive immunohistochemistry markers. The tumor cells often show well-defined cell borders and nuclei with vesicular chromatin and prominent nucleoli. Multinucleated tumor giant cells and pleomorphism are focally seen in a subset of cases, and focal spindle cell sarcomatoid morphology is occasionally present. The extent of mitotic activity closely parallels the degree of cellular pleomorphism. An intense striking inflammatory infiltrate of neutrophils, small lymphocytes, or eosinophils is often seen.,,
However, many tumors previously diagnosed as HS before development of specific immunohistochemical markers are now recognized to represent large-cell non-Hodgkin's lymphomas (DLBCL or ALCL). The differential diagnosis also includes malignant melanoma, metastatic carcinoma, and soft-tissue sarcoma. Benign entities with histiocytic proliferation, such as hemophagocytic syndrome and storage disorders, can be generally excluded because of malignant cytologic features. Immunohistochemistry plays an important exclusionary role in evaluating the differential diagnosis of HS. CD 68 and CD 163 are the best available immunohistochemical markers for HS. S-100 exhibits variable results in histiocytic tumors. CD45 staining is recommended to establish hematopoietic origin and differentiate from morphologically similar soft-tissue neoplasms. Antibodies for melanocytic, epithelial, and lymphoid cell markers are negative. Molecular studies can show monoclonal IgH gene rearrangements.,,
HSs show up as intensely FDG (fluoro-2-deoxy-d-glucose) avid masses on positron emission tomography scans, but radiological findings are nonspecific., HS often presents at an advanced clinical stage with aggressive clinical course, poor response to chemotherapy, and high mortality rate.,,,, Treatment options for HS include surgery, chemotherapy, and radiotherapy. Surgical resection with wide margins is the gold standard of treatment. Radiotherapy may play an important role in cases, where a complete resection is not possible. Chemotherapy regimens remain controversial, with poor prognosis. Tumor size and stage are believed to be important factors in the prognosis.,
ENHS in colon is an extremely rare tumor and can mimic other large-cell or epithelioid neoplasms. Histopathological findings and immunohistochemical markers are helpful in diagnosing this type of rare entity.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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Department of Pathology, AMRI Hospitals, Kolkata - 700 029, West Bengal
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3]