72
(C) Mucoepidermoid carcinoma and adenosquamous
carcinoma
Esophageal mucoepidermoid carcinoma and adenosqua-
mous carcinoma had a mixture of malignant squamous and
mucinous producing cells. Mucoepidermoid carcinoma shows
an intimate mixture of malignant squamous cells, mucous
secreting cells and cells of intermediate type. On the other
hand, in adenosquamous carcinoma, the malignant squamous
and the glandular components are well demarcated from each
other.
Majority of the cases of this group of carcinomas were
reported in Asian populations. The largest series having these
two types of esophageal carcinomas have been reported in
Hong Kong in 1994 [ 12 ]. They have reported 20 cases of
these carcinomas and compared the features with other squa-
mous cell carcinomas of the esophagus. The site distribution of
these carcinomas follows that of the esophageal squamous cell
carcinoma with around half of the carcinomas located in the
middle third of the esophagus [ 13 , 14 ]. As a whole, this group
of carcinoma comprises approximately 2% of carcinomas of
esophageal or esophagogastric junction [ 12 , 13 ]. For esopha-
geal mucoepidermoid carcinoma only, Chen and colleagues in
China, who presented the features of 36 cases, is the largest
series of mucoepidermoid carcinoma in the esophagus [ 15 ]. Ni
and colleagues in China, who presented the features of 39
cases, is the largest series for adenosquamous carcinoma in the
esophagus [ 16 ]. They also reported the same findings that the
prognosis did not differ from that of patients with squamous
cell carcinoma or adenocarcinoma.- (A) Conventional adenocarcinoma is the most often accounted
histology. A common feature is duplication of the muscularis
mucosae. Thus, carcinoma that involves in between the two
layers of the muscularis mucosae are considered as intra-muco-
sal carcinoma.
Adenocarcinoma is graded as grade 1 (well differentiated),
grade 2 (moderately differentiated), and grade 3 (poorly dif-
ferentiated). The grading depends on the ease of identification
of glandular architecture in the adenocarcinoma. Grading of
adenocarcinoma could be subjective to the pathologist’s inter-
pretation. In the current American Joint Committee on Cancer
Staging Manual, the proportion of adenocarcinoma with well-
formed glands is used as the criterion for grading (see Chapter
in Staging) [ 2 ]. Nevertheless, for practical purposes in clinical
management or research, it is important to differentiate
between grade “1” or “2” adenocarcinoma with grade “3”
adenocarcinoma. It is worth noting that the differentiation
between grade 3 adenocarcinoma and the earlier grades (grade
Alfred K. Lam