Diagnostic and treatment challenges of a case of primary cutaneous signet-ring cell/histiocytoid carcinoma of the eyelid

BACKGROUND: Primary cutaneous signet-ring cell/histiocytoid carcinoma of the eyelid is an extremely rare but aggressive neoplasm diagnosed primarily in elderly men. Until now there are 32 published cases of signet-ring cell carcinoma or histiocytoid carcinoma of the eyelid. We report the clinical, radiographic and histological features of the 33rd reported case of PCSRCC in the eyelid of a 73-year-old male, and review diagnostic and treatment challenges of this rare entity. CASE PRESENTATION: Our case highlights a 73-year-old male who was referred for surgical correction of right eye ptosis that was present for 2 years. Upon assessment, he was noted to have an upper lateral orbital rim mass. Computed tomography (CT) noted ill-defined soft tissue thickening anterior to the right globe, predominantly pre-septal but with slight post-septal extension. The pathology revealed diffusely and deeply infiltrating tumour cells extending through the dermis, subcutis, orbicularis muscle bundles and nerve fibers; the tumour cells were noted to have a monotonous histiocytoid appearance with foamy granular eosinophilic cytoplasm. At high magnification, intracytoplasmic vacuoles and occasional intermixed signet ring cells were identified. Immunohistochemical staining revealed the tumour cells to be AE1/AE3, CK7, GCDFP-15, E-cadherin, androgen receptor stain and GATA3 positive. Final pathology report confirmed the diagnosis of primary cutaneous signet-ring cell/histiocytoid carcinoma. Further imaging failed to identify a distant primary malignancy or metastatic disease. The decision was made to attempt surgical excision of the tumor. After the bulk of the grossly apparent tumor was removed, intraoperative frozen sections were sent. Superficial biopsies of the right periorbital region were performed, which revealed extension significantly further than the gross disease. Thereafter, the patient underwent a wide orbital exenteration with reconstruction using a temporary split-thickness skin graft. Due to positive margins on final permanent sections, the patient underwent further wide resection with free muscle-skin flap reconstruction followed by adjuvant radiation treatment. CONCLUSION: Our case represents the 33rd case of primary signet-ring cell/histiocytoid carcinoma of the eyelid in a 73-year-old male, the first documented case with GATA3 positivity and the second documented case with androgen receptor stain positivity.