Primary mucinous adenocarcinoma of the thymus: A case report and review of the literature

Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9073, USA.
Archives of pathology & laboratory medicine (Impact Factor: 2.84). 03/2006; 130(2):201-4. DOI: 10.1043/1543-2165(2006)130[201:PMAOTT]2.0.CO;2
Source: PubMed


Primary thymic mucinous adenocarcinoma is extremely rare; to our knowledge, only 2 cases have been reported to date. We describe a third case of primary mucinous adenocarcinoma of the thymus in a 41-year-old man who presented with an anterior mediastinal mass with subsequent metastasis to the lung. The initial diagnosis was of metastatic mucinous adenocarcinoma, but extensive clinical workup of the patient failed to reveal a primary tumor elsewhere in the body. The specific identification of mucinous adenocarcinoma as a primary thymic neoplasm can be difficult or impossible. Morphologic and immunophenotypic similarities to mucinous adenocarcinomas of the gastrointestinal tract can pose diagnostic challenges for surgical pathologists, especially in small biopsy specimens.

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Available from: Kyle Molberg, May 01, 2014
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    • "CEA in 23% (mostly seen in mucinous subtype), B-HCG in 0.38% (only in conventional subtype) and CA19-9 in 11% (one papillary, one NOS and two mucinous subtypes, including ours). Immunohistochemistry on different subtypes were performed in a limited number of papers and showed positivity in CK7 (7/11), CK20 (6/9), CEA (6/9), Leu M1 (4/5), B-HCG (1/2), CDX-2 (3/4), Muc2 (1/2), Muc5 (2/2), CD5 (8/12), P63 (1/2), CA-19-9 (3/3), CAM5.2 (2/2), CK5,6 (1/2), P53 (2/2), Her2 (1/2) [4-7,9-18]. "
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    ABSTRACT: Background Primary adenocarcinoma of thymus is extremely rare. Case presentation This is a case of primary adenocarcinoma with intestinal differentiation and focal mucin production in the thymus. Thymic cyst was associated with this tumor. Intestinal differentiation was confirmed by immunohistochemical stain with positivity for CDX-2, CK20, villin, MOC31 and focal positivity of CK7. Array comperative genomic hybridization (CGH) analysis showed a complex pattern of chromosomal imbalances including homozygous deletion at the HLA locus in chromosomal region 6p21.32. Conclusion This rare tumor shows a similar genetic aberration with other studied thymic epithelial tumors.
    Full-text · Article · May 2013 · BMC Clinical Pathology
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    • "These findings are close to those seen in a case reported by Choi et al.4 In our case, the cysts met all the diagnostic criteria for an acquired multilocular thymic cyst.7 It has been postulated that the thymic epithelium would potentially undergo glandular differentiation, as evidenced by the presence of ciliated and mucinous cells in the epithelium of the cysts.4 "
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    ABSTRACT: Primary thymic mucinous adenocarcinoma is an extremely rare aggressive subtype of thymic carcinoma. With a review of literatures, only nine cases have been reported up to present. A 36-year-old woman was admitted for further evaluation and treatment of a mediastinal mass. The patient had no medical history of cancer. The clinicoradiological examination disclosed no tumor elsewhere. After the surgical excision of mediastinal mass, it was grossly a round semi-solid mass with mucin-filled cystic areas. Microscopically solid areas showed cords, small nests and dilated glands infiltrating the fibrotic parenchyma, while the cystic areas were lined by mucinous epithelium with tumor cells floating in extracellular-mucin pools. Some cystic walls underwent malignant transformation of the benign thymic epithelium. Immunohistochemically, the tumor cells were positive for cytokeratin (CK) 7, CK20, CD5, and CDX-2, and negative for thyroid transcription factor-1. In conclusion, the mucinous thymic adenocarcinoma should be recognized as a separate histopathological entity and considered in the differential diagnosis of mediastinal carcinomas.
    Full-text · Article · Aug 2012
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    ABSTRACT: Most adenocarcinomas of the mediastinum are metastatic lesions. Primary thymic adenocarcinomas are extremely rare neoplasms. We could find only 12 cases reported in the literature; of these 12, only 4 were of the mucinous subtype. We report 2 additional cases of the mucinous subtype, including a previously unreported mucinous variant with numerous psammoma bodies. The first case in a 61-year-old woman resembled a mucinous (colloid) carcinoma of other organs such as the breast and colon. It consisted of islands and strips of tumor cells floating in large pools of extracellular mucin. A unique feature of this tumor was the presence of numerous psammoma bodies. Immunohistochemically, the tumor cells were positive for cytokeratin (CK) 7 and negative for CD5. The second case in an 82-year-old woman was a mucinous adenocarcinoma arising from a thymic cyst with areas of transition from benign to dysplastic epithelium. The tumor cells formed dilated glands, cords, and small nests that infiltrated the thymic cyst wall and exhibited evidence of mucin production. Immunohistochemically, the tumor cells were positive for CK 7 and focally positive for both CD5 and CK 5/6. Mucinous adenocarcinoma, with or without, psammoma bodies, may be of primary thymic origin and should be considered in the differential diagnosis of malignant mediastinal tumors. These 2 cases provide further documentation of the rare occurrence of primary mucinous adenocarcinomas of the thymic gland.
    No preview · Article · Oct 2007 · American Journal of Surgical Pathology
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