adenosquamous cell carcinomas of the gallbladder are rare.
Microscopic image of adenosquamous
adenosquamous carcinoma contains a mixture of malignant
glandular and squamous components.
squamous cell carcinoma constitutes only 1% of all
malignant gallbladder tumors and consists of cords,
islands, or sheets of malignant squamous cells separated by
dense fibrous stroma.
most likely arise in areas of previous squamous metaplasia,
and their histologic features may vary from anaplastic to
well-differentiated, keratinizing squamous cell carcinoma.
clinical behavior and clinicopathologic characteristics are
very different from those of adenocarcinoma.
characteristically tend to arise from the gallbladder fossa
and present rapid and invasive growth, which results in
direct invasion into the liver and adjacent organs.
In contrast to
their aggressive tendency and advanced stage, they usually
do not present lymph node metastasis or peritoneal seeding.
Liver metastases are more frequently seen, however, than
with the adenocarcinoma.