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Epidermal inclusions in abdominal lymph nodes. Report of two cases studied immunohistochemically
1Department of Pathology, Hamamatsu University School of Medicine, Shizuoka, Japan.
Insights
Gastric adenocarcinoma lymph nodes unexpectedly contained epidermal tissue, resembling pancreatic lymphoepithelial cysts. No metastasis was observed, suggesting a non-neoplastic incidental finding.
Area of Science:
- Gastroenterology
- Surgical Pathology
- Oncology
Background:
- Histological examination of abdominal lymph nodes from two male patients with gastric adenocarcinoma.
- Investigation focused on incidental findings within lymph nodes unrelated to metastasis.
Observation:
- Presence of epidermal epithelium, squamous epithelial nests, and epidermal cysts within lymph nodes.
- Adjacent pancreatic tissue was noted near these epidermal inclusions.
- Some squamous nests exhibited cyst formation or co-occurred with mucin-containing cells.
Findings:
- Immunohistochemical analysis showed weak CA19-9 staining in squamous nests, with negative results for CEA and CA125.
- The observed lesions were histologically similar to lymphoepithelial cysts typically found in the pancreas.
- No evidence of metastasis from the gastric adenocarcinoma was detected in the examined lymph nodes.
Implications:
- Suggests a potential for non-neoplastic epithelial inclusions within lymph nodes in gastric cancer patients.
- Highlights the importance of differentiating these incidental findings from metastatic disease.
- May inform differential diagnoses in pancreatic and gastric pathology, particularly concerning cystic lesions.
Abstract:
Abdominal lymph nodes from men aged 48 and 62 years with gastric adenocarcinoma were examined histologically. A few of the lymph nodes contained epidermal epithelium, although there was no metastasis. Scattered squamous epithelial nests and epidermal cysts were found within the lymph nodes, and small amounts of pancreatic tissue were present adjacent to the epidermal inclusions. Some squamous cell nests showed cyst formation, and some others showed squamous cell nests together with mucin-containing cells forming luminal structures. Immunohistochemically, the squamous cell nests stained weakly for CA19-9 but were negative for CEA or CA125. These lesions were considered to be similar to lymphoepithelial cysts of the pancreas.