Abstract
Primary cutaneous signet-ring cell/histiocytoid carcinoma of the eyelid (PCSHCE) is an exceedingly rare (< 50 cases reported) adnexal malignancy presenting clinically as an insidious, unilateral thickening and erythema of the eyelid and periocular skin (monocle tumor). As the clinical presentation mimics an inflammatory process, diagnosis is often delayed. We present the case of a 66-year-old male with a 2-year history of right eye/facial swelling. Outside biopsy demonstrated adenocarcinoma involving dermis and in-house MRI showed diffuse soft tissue swelling involving the right orbit and surrounding skin/soft tissues leading to a right orbital exenteration and neck dissection. Gross examination revealed diffuse thickening of the periorbital skin/soft tissue; histopathologic exam showed a highly infiltrative adenocarcinoma composed of single cells with histiocytoid/signet ring cell features, amphophilic cytoplasm, and somewhat pleomorphic nuclei with vesicular chromatin and prominent nucleoli. The tumor cells were immunoreactive for CK7, GATA3, EMA, androgen receptor and focal CEA while negative for p63, Sox10, TTF1, CDX2, PAX8 and Mammaglobin. Tumor cells retained expression of E-Cadherin. The clinical and histopathologic features, in addition to ruling out possible metastatic adenocarcinoma, were consistent with PCSHCE. The tumor was locally advanced with lymph node metastasis. Although CDH1 mutations have been described in few PCSHCE examples, outside next generation sequencing (NGS; STRATA) failed to reveal this aberration or any targetable mutations. Following surgical treatment, the patient received six weeks of radiation therapy. One year after initial diagnosis, PET scan revealed no evidence of residual/metastatic disease. In summary, we present a rare case of PCSHCE with NGS results.
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