The Enigmatic ‘Swiss Cheese’ in macroscopic tissue pathology

Swiss cheese appearance denotes the presence of multiple holes known as ‘eyes’ in the hue of the tissue background. This is a very classic and distinct visual identity in histopathology. It is interesting to note that this appearance is spoken of in the pathology of different organ systems of the body like in the brain, lungs, endometrium, and salivary gland pathologies. Even more interesting is the fact that this term is used in the interpretation of ultrasound images, CT images, and MRI but stands to be most frequently employed in the context of histopathology. In histopathology, the common tumour pathology, which shows this pattern, is adenoid cystic carcinoma of the salivary glands. This pattern can also be seen in polymorphous adenocarcinoma (PAC), adenocarcinoma, and adenoid cystic carcinoma of other organs and tissues. Few lesions, like sclerosing lipogranuloma, silicon granulomas, and lymphadenitis, also show this pattern. A science of observation of the tissue sections on a slide is not new. Many a times, a clue on the cell types, cell arrangements, and tissue types can be deciphered from looking at a macroscopic tissue section image. Here, we present a case of sebaceous lymphadenoma (LAD), which shows a classic Swiss Cheese appearance on macroscopy of the tissue section [Figure 1]. The section shows a well-delineated tumour area separated by mature fibrous tissue along with normal parotid architecture on the other side. Specks of serous, darkly stained acini are seen alternating with clear lipomatous areas. The tumour section showing a Cribriform or Swiss Cheese pattern with holes or eyes of 1 mm and less than 1 mm, clustered in a well-stained basophilic area of cells and tissues. Such a presentation of pattern on macroscopic tissue section analysis can also be seen in lesions, like trichoadenomas and other similar tumours.Figure 1: (a) Macroscopy of hematoxylin and eosin stained section of sebaceous lymphadenoma [H&E stain, x1]. (b) Hand drawn illustration of the same. 1. Cribriform/Swiss Cheese pattern of tumour tissue on macroscopy, 2. Fibrous mature collagenous stroma delineating the tumour from the normal parotid tissue, 3. Basophilic serous acini alternating with adipocytes in the normal parotid salivary gland tissue, 4. “Eyes”/perforating pattern in the tumour tissueThis pattern is unique and classic in appearance in the depiction of the macroscopic appearance of the tissue section. It can be used as a clue to diagnosis by a diagnostic pathologist. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.