Moderately to poorly differentiated adenocarcinoma invading a leiomyoma: A case report

Table 2 Immunohistochemistry

Marker	Result	Clinical significance
Panel A: Mesenchymal tumor differentiation
SMA	Positive	Supports leiomyoma origin
Desmin	Positive	Supports leiomyoma origin
CD117 (KIT)	Focally positive	Helps rule out GIST
DOG-1	Negative	Helps rule out GIST
SDHB	Intact	Rules out SDH-deficient GIST
CD34	Negative/intact vascular staining	Not typical for GIST in this context/no evidence of lymphovascular invasion identified
S-100	Negative/nerves highlighted	Helps rule out schwannoma/no perineural invasion identified
Panel B: Epithelial tumor characterization
CK7	Positive	Consistent with gastric origin
CK20	Rarely positive	Common profile for gastric adenocarcinoma
Mucin-2	Negative	Suggests intestinal-type differentiation
Mucin 5AC	Focally positive	Suggests gastric/gastrointestinal differentiation
Mucin 6	Rarely positive	Suggests gastric differentiation
CDX-2	Positive	Supports intestinal-type differentiation
Panel C: Proliferation and tumor suppressor markers
Ki-67	1%-5% +/80% (in hotspot regions)	Indicates a high proliferative index
P53	90% positive, located in the cell nucleus. Positive tumor cells account for approximately 85%	Suggests underlying TP53 gene mutation
Her-2	(1+) negative, positive tumor cells account for approximately 10%	May have implications for targeted therapy
MSH-6	(+) located in the cell nucleus. Positive tumor cells account for approximately 10%	The mismatch repair function is missing
MlH-1	(+) located in the cell nucleus. Positive tumor cells account for approximately 95%	Prompt to save the mismatch repair function

SMA: Smooth muscle actin; KIT: Proto-oncogene receptor tyrosine kinase; DOG-1: Discovered on gastrointestinal stromal tumor-1; SDHB: Succinate dehydrogenase B; CK: Cytokeratin; CDX-2: Caudal-type homeobox 2; MSH-6: MutS homolog 6; MlH-1: MutL homolog 1; GIST: Gastrointestinal stromal tumors; SDH: Succinate dehydrogenase.