Thymic tumor with adenoid cystic carcinomalike features: A clinicopathologic study of 4 cases

Luca Di Tommaso, Elisabetta Kuhn, Michael Kurrer, Andreas Zettl, Alex Marx, Hans Konrad Müller-Hermelink, Massimo Roncalli, Juan Rosai

Research output: Contribution to journalArticlepeer-review


Thymic carcinomas are rare malignant neoplasms which comprise several histologic subtypes. Adenoid cystic carcinoma (ACC) is included among these subtypes even if it has never been formally reported. We evaluated the clinical, radiologic, morphologic, immunohistochemical, and genetic features of 4 cases of thymic neoplasms with ACC-like features retrieved from the authors' consult files. Most cases affected adult/elderly males (mean 68.5 y; range: 63 to 77 y; M:F ratio=3:1), and were asymptomatic. The clinical history (no evidence of ACC in other sites), radiologic findings (a mass in the thymic region), and morphologic features (residual thymic tissue at the periphery of the neoplasm) strongly supported their primary thymic nature. Grossly, most of the tumors presented as multicystic lesions. On microscopic examination there were true glandular spaces filled with periodic acid-Schiff+material, and pseudocysts containing stromal mucin, collagen IV, and laminin. Features favoring malignancy were overtly infiltrative margins (2/4), mitotic figures (2/4), cytologic atypia (1/4), vascular invasion (1/4), absence of organoid thymuslike pattern (4/4), and absence of immature (TdT+) T lymphocytes (3/3). Necrosis and nerve invasion were not observed. The tumor cells showed the following immunophenotype: p63+(3/3), CK34betaE12+(3/3), CD5+ in scattered cells (1/3), CD117- (3/3), chromogranin-(2/2), synaptophysin-(2/2), and CD56- (2/2). MIB-1 ranged from 1% to 10%. Comparative genomic hybridization revealed an isolated gain of chromosome 8 in 1/3 cases. One patient is alive and well after 20 months, 1 died of another cause 5 years later, and 2 were lost at follow-up. Exceptionally, primary thymic tumors may exhibit histologic features resembling those of ACC of salivary glands. They may be well circumscribed and cytologically bland or invasive and cytologically atypical. In either case they lack an organoid thymuslike pattern and immature T lymphocytes. We have interpreted them as a microscopic subtype of well-differentiated thymic carcinoma of low-grade malignancy, an impression supported by the admittedly limited follow-up information.

Original languageEnglish
Pages (from-to)1161-1167
Number of pages7
JournalAmerican Journal of Surgical Pathology
Issue number8
Publication statusPublished - Aug 2007


  • Adenoid cystic carcinoma
  • CGH
  • Immunohistochemistry
  • Thymic carcinoma
  • Thymus

ASJC Scopus subject areas

  • Anatomy
  • Pathology and Forensic Medicine


Dive into the research topics of 'Thymic tumor with adenoid cystic carcinomalike features: A clinicopathologic study of 4 cases'. Together they form a unique fingerprint.

Cite this