Feeling Something Deeper: A Case of Hyalinizing Clear Cell Carcinoma of Lung Primary With Suspected Lynch Syndrome

Document Type

Conference Proceeding

Publication Date

5-2024

Publication Title

American Journal of Respiratory and Critical Care Medicine

Abstract

Hyalinizing Clear Cell Carcinoma (HCCC) is a type of Salivary Gland-type Tumor (SGT) that can present as a rare subset of lung neoplasms. The association of HCCC with loss of mismatch repair expression (MMR) has not yet been described. Our case is that of a 74-year-old female who presented with a concern for palpable breast mass. Her past medical history is significant for invasive ductal carcinoma of the left breast, status-post lumpectomy, chemotherapy, and radiation therapy. MRI of the breast showed no evidence of breast malignancy, though a left perihilar enhancing mass was visualized. A contrasted CT of the chest was obtained which showed a 3.4 x4.4 x 3.1 cm left perihilar mass. Until this point, the patient was without cardiopulmonary symptoms and the imaging findings were incidental. The patient underwent video bronchoscopy with ultrasound guided biopsy of the left upper lobe superior lingula. Biopsy results showed a bland proliferation of epithelial cells with generally round nuclear contours, rare small nucleoli, and moderate amounts of eosinophilic cytoplasm overlying a focally myxomatous stroma. Immunohistochemistry (IHC) staining was positive for p40 and negative for GATA-3, INSM1, TTF-1,and SOX 10. Given similarity in morphology between HCCC and other SGT’s, gene rearrangement studies were performed and identified EWSR1 rearrangement, which is often seen in HCCC1.PET-CT showed focal tracer uptake corresponding with the known left perihilar mass with no abnormal focal hypermetabolism in the region of the salivary glands to suggest a site of primary malignancy. The patient subsequently underwent surgical resection of the tumor. MMR protein expression was performed on the resected specimen and significant for clonal loss of nuclear expression of MSH6 only, indicating a high probability of Lynch Syndrome. Repeat PET-CT oneyear later showed no evidence for residual/recurrent carcinoma or distant metastasis. HCCC remains a rare subtype of SGT’s involving the lung and a diagnostic challenge by biopsy. Moreover, our patient’s pathology has demonstrated loss of MMR protein expression, which has not been previously described in association with HCCC of lung primary on our review of the literature. While loss of MMR protein expression has been described previously in clear cell carcinoma of theovaries2, our patient did not demonstrate any PET avid disease within the abdomen or pelvis. Given the high probability of Lynch Syndrome associated with loss of MSH6 expression, our patient was offered cancer genetic testing though she declined to pursue testing after counseling.

Volume

209

Issue

Suppl

First Page

A7488

Comments

International Conference of the American Thoracic Society, May 17-22, 2024, San Diego, CA

DOI

10.1164/ajrccm-conference.2024.209.1_MeetingAbstracts.A7488

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