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Case Report
Squamous cell carcinoma of the rectum, primary or metastatic?
Department of Pathology, University of Louisville, Louisville, Kentucky, USA
Key words
squamous cell carcinoma of the rectum; dermoid cyst of the ovary with malignant transforamtion; squamous cell
carcinoma of the ovaryJ Gastrointest Oncol 2011; 2: 262-264. DOI: 10.3978/j.issn.2078-6891.2011.038
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Introduction
Primary squamous cell carcinoma of the rectum is very rare.
In this article we report a case of squamous cell carcinoma
arising from an ovarian dermoid cyst presenting as a rectal
mass with gastrointestinal symptoms. To the best of our
knowledge, this clinical presentation has not been reported
before. This article emphasizes the importance of applying
the appropriate guidelines before assigning the diagnosis
of primary colorectal squamous cell carcinoma , since the
treatment and the management are different.
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Case report
A 49-year-old female was transferred to University Hospital
from an outside facility. She had a three month history of
pelvic pain, hematochezia and difficulty defecating.
A CT scan revealed a necrotic colorectal mass most
consistent with malignancy, which was seen eroding into
a large teratoma within the pelvis. Rectal contrast was
extravasating outside the bowel lumen and filling the
teratoma consistent with a fistulous communication (Fig 1).
Her past medical history and family history were
negative for malignancy. Because of her gastrointestinal symptoms, she was referred to the gastrointestinal service for colonoscopy. On digital rectal examination a palpable
mass was noted. The colonoscopy confirmed the presence of
a partially obstructing ulcerated rectal mass (Fig 2) which
was biopsied. The colonoscopy impression was consistent
with primary rectal carcinoma. Microscopic examination
of the biopsies revealed squamous cell carcinoma with
adjacent normal colonic mucosa. The differential diagnosis
included primary squamous cell carcinoma versus
metastatic origin. Extension from the anal canal was also
considered in the differential diagnosis. With the working
diagnosis of teratoma with squamous cell carcinoma
transformation extending to the rectum, the patient
underwent total abdominal hysterectomy with bilateral
salpingo-oophorectomy and low Hartmann resection of the
rectum and sigmoid colon. The resection specimen revealed
that the ulcerated rectal mass was directly adherent to the
necrotic ovarian cyst (Fig 3). Microscopic examination
supported the diagnosis of squamous cell carcinoma arising
from ovarian dermoid cyst and extending to the wall of the
rectum (Fig 4). The patient tolerated surgery well and was
sent home in stable condition.
Figure 1 Rectal contrast was extravasating outside the bowel lumen and filling the teratoma consistent with a fistulous communication
Figure 2 Colonoscopy view of the rectal mass eroding into the lumen
Figure 3 Colonoscopy view of the rectal mass eroding into the lumen
Figure 4 Invasive squamous cell carcinoma invading into the rectal wall
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Discussion
Primary colorectal squamous cell carcinoma (SCC) is one
of the rare malignancies of the gastrointestinal tract (1).
It is part of the 2010 WHO classification, however pure
squamous cell carcinoma is very rare and the incidence of
(SSC) is far less than adenosquamous cell carcinoma (2). In
1919 Schmidtmann described the first case of squamous cell
carcinoma of the large intestine localized to the cecum (3).
Since that time, less than 100 cases have been reported in
the English literature.
Of all cases of primary squamous cell carcinoma of the
lower gastrointestinal tract, the rectum is the most frequent
location for the disease, followed by the right colon (4).
Primary squamous cell carcinoma of the rectum affects
individuals between the ages of 39 to 93, with a mean age
of 57, years and is more frequent in women than in men (4).
Squamous cell carcinoma can be seen in association with
inflammatory and infectious processes involving the colon
and rectum, such as ulcerative colitis, Schistosomiasis,
Entamoeba histolytica and human papilloma virus (HPV)
(4).
Since primary colorectal SCC are very rare. Williams
et al. have suggested guidelines before making a definitive diagnosis of primary colorectal SCC, which include ruling out the following entities: other primary sites, a squamouslined fistula tract to the affected bowel and an extension of
the tumor from the anal canal SCC. This can be established
through careful clinical investigation and necessary
radiographic images.
On the other hand mature cystic teratoma of the
ovary is a common disease accounting for 10%–20% of
all ovarian neoplasms (6). They are composed of well
differentiated derivation of the three germ cell layers
(endoderm, mesoderm, ectoderm). Complications of the
mature cystic teratomas include torsion (16%), malignant
transformation (2%), rupture (1%–2%), and infection (1%)
(6,7).
Malignant transformation (MT) of an ovarian cystic teratoma is rare and usually occurs in postmenopausal
women (8). The most common type of mal ignant
transformation is SCC arising from the squamous lining
of the cyst, accounting for 80%–83% of cases, followed
by adenocarcinoma (7%) and sarcoma (7%) (2). Primary
SCC of the ovary is very rare (9). Ovarian squamous cell
carcinoma might be associated with high risk human
papilloma virus (10).
Most cases of ovarian SCC arise from a mature cystic
teratoma, and are classif ied in the germ cell tumor
category, although a few cases develop in association
with endometriosis (9,11). The prognosis of MT is highly
dependent on age, stage, and optimal cytoreduction, and
there is no standard adjuvant treatment (12). Patients with
SCC arising in mature cystic teratomas usually present with
abdominal complaints (pain and mass) (6,10). These tumors
grow slowly and cause minimal symptoms until they are
very large or they become complicated (6).
The pathogenesis of the MT arising in ovarian MCT
is not well understood. It is possible that since most
MCTs are diagnosed during the reproductive age and
MT is predominantly seen in the postmenopausal period,
malignant transformation could be related to the long-term
existence of non-removed MCT with prolonged exposure
to various carcinogens in the pelvic cavity (8,10). Malignant
transformation of MCT is usually diagnosed after removal
of the tumor because it cannot be readily differentiated
from an uncomplicated MCT or other ovarian tumors preoperatively
(8).
This case has a unique presentation, showing
gastrointestinal symptoms , which was initially
misleading. To the best of our knowledge squamous
cell carcinoma arising from an ovarian dermoid cyst
presenting as a rectal mass with gastrointestinal
symptoms has not been previously reported. This case
emphasizes the importance of the guidelines suggested
by William et al, in the evaluation of patients with
colorectal SCC. Since primary SCC of the colorectal are
rare, other primary sites and an extension from the anal
canal should always be considered.
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References
Cite this article as: Alatassi H, Moghadamfalahi M. Squamous cell carcinoma of the rectum, primary or metastatic? J Gastrointest Oncol. 2011;2(4):262-264. DOI: 10.3978/j.issn.2078-6891.2011.038
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