Sinusoidal Growth Pattern of Hepatic Melanoma Metastasis: Implications for Histopathologic Diagnosis. (18th June 2022)

• Record Type: Journal Article
• Authors: Szczepanski, Julianne M.; Mendiratta-Lala, Mishal; Fang, Jiayun M.; Choi, Won-Tak; Karamchandani, Dipti M.; Westerhoff, Maria
• Is Part Of: American journal of surgical pathology. Volume 46:Number 6(2022)
• Page Start: 832
• Page End: 839
• Publication Date: 2022-06-18
• Subjects: liver biopsy -- liver metastasis -- metastatic melanoma -- ocular melanoma -- histopathologic growth patterns; Pathology, Surgical -- Periodicals; 617.0705
• DOI: 10.1097/PAS.0000000000001835
• Languages: English
• ISSNs: 0147-5185

Abstract

Abstract : Metastatic tumors interface with liver in multiple patterns, of which, the rare "sinusoidal" growth pattern can be subtle and easily overlooked on biopsy. We sought to characterize the metastasis-to-liver interface patterns of melanoma compared with other tumor types and assess the incidence of metastatic melanoma in histologically normal-appearing targeted liver lesion biopsies. Liver lesion samples from 54 melanoma patients were assessed. Nearly normal-appearing cases, defined as no obvious malignancy on routine hematoxylin and eosin stain (n=24), were stained with SOX10 and confirmed with MelanA. Tumor-to-liver interface patterns were determined in biopsies overtly positive for metastatic melanoma (n=30) versus other hepatic metastases as controls (colon, n=28; breast, n=20; pancreaticobiliary, n=20; and neuroendocrine, n=28). Of the 24 nearly normal-appearing liver biopsies from melanoma patients, 3 had subtle melanoma cells detected in sinusoids, confirmed with immunohistochemistry. Of 30 livers overtly positive for melanoma, 8 showed the sinusoidal pattern, compared with none in other metastases. In total, 11/33 (33%) cases of metastatic melanoma liver biopsies demonstrated the sinusoidal pattern. We describe 11 metastatic melanoma cases in liver with the rare sinusoidal pattern, 3 of which were subtle and easy to miss on routine hematoxylin and eosin stain. Given that sinusoidal metastasis does not elicit a tissue reaction, it is prudent for the pathologists to be aware of this pattern of metastases and have a low threshold to order immunostains for accurate diagnosis and optimal patient care.