Adenosquamous Carcinoma of Gallbladder – A Case Report

Gallbladder cancer is an uncommon malignancy and majority of these carcinomas are adenocarcinomas. Adenosquamous carcinoma of gallbladder is a rare histopathological subtype of gallbladder carcinoma. It usually presents with symptoms of cholelithiasis like epigastric pain, nausea and bloating. On clinical examination, tenderness is usually present. Radiologically in most of the cases, gallstones are found leading to the diagnosis of cholelithiasis for which cholecystectomy is done. Gallbladder carcinomas are found mostly as an incidental finding on microscopic examination of cholecystectomy specimen. This disease is curable if diagnosed earlier but in most of the cases they present at advanced stages when resection is not possible and prognosis is poor. As this disease is extremely rare so published information is largely based on the case reports and case series. This is a case of 60 years old female patient who underwent cholecystectomy for cholelithiasis with incidental finding of Adenosquamous carcinoma on histopathology report.
Key words: Adenosquamous, carcinoma, cholelithiasis, Gallbladder.

Gallbladder carcinoma is an uncommon but lethal malignancy. Adenosquamous carcinoma is a rare neoplasm accounting for 1-12 % of all the gallbladder carcinomas¹. Only one-third of cases are diagnosed pre operatively while the remaining are diagnosed incidentally on histopathological examination of cholecystectomy specimen². Adenosquamous carcinoma of gallbladder is a locally aggressive neoplasm with poor prognosis³.
We present a case of 60 years old female patient who underwent cholecystectomy for cholelithiasis with final diagnosis of Adenosquamous carcinoma on histopathology report.

A 60 years old lady presented in a private clinic in a remote area of khyber pakhtunkhwah, Pakistan with complain of epigastric pain. She belongs to a middle class family and her family history for any type of carcinoma was unremarkable. After clinical examination, ultrasound abdomen was suggested which gave the opinion of cholilithiasis as it showed multiple stones in the lumen. Elective cholecystectomy was planned for the cure of cholilithiasis and the specimen was sent for histopathological examination.
On gross examination, gallbladder measured 9x4cm and the lumen showed multiple black stones. Two polypoidal nodules were seen in the body of gallbladder, the largest one measured 1.5x1.3x1.3cm while smaller one measured 0.8x0.8x0.5cm (Figure 1). Microscopoic examination of the large polyp revealed a well differentiated squamous carcinoma and smaller polyp showed an adenocarcinoma. The tumor was invading the muscular layer. The margins were free of tumor (Figure 2).
Immunohistochemical stains showed CK7 and CK 20 positivity in adenocarcinoma and p 63 was negative in the polyp containing adenocarcinoma. CDX2 was focally positive (Figure 3)

Figure 1: Gallbladder on examination showed one large polyp (small arrow), small polyp (long arrow) and contained multiple small black coloured stones (arrow head). The distance between the two polyps was 2.5cm.

Figure 2: Microscopic examination of the gallbladder showed (A) Squamous cell carcinoma in the larger polyp. (B) Adenocarcinoma in the smaller polyp (H&E X40).

Figure 3: A, B, CK7 and CK 20 immunohistochemical stains are positive in the neoplastic cells, C, p63 is negative in the polyp containing adenocarcinoma
while CDX2 is focally positive in the polyp containing adenocarcinoma (40× magnification).

Gallbladder carcinoma is an aggressive malignancy with poor outcome⁴. It is the most common cancer of biliary tract and 5th most common malignancy of gastrointestinal tract⁵. Its increased incidence is seen in India, Pakistan, East Asia, Eastern Europe, South America, Chile and Columbia⁶. The most common histologic subtype of gallbladder cancer is adenocarcinoma which represents approximately 76–90% of total gallbladder carcinoma cases. Pure squamous and adenosquamous carcinoma constitutes 2–10% of cases and papillary tumors constitute 5–6% of cases⁷. Adenosquamous carcinoma of the gallbladder is composed of both glandular and squamous components. If the squamous part is 25%–99% of the tumor, then it is called as adenosquamous carcinoma⁸. Literature on adenosquamous carcinoma is limited because of its rarity. Juan C Rao conducted a large cohort study on 606 cases of gallbladder adenocarcinoma in which squamous cell carcinomas constituted 1% of the total cases and 4% were adenosquamous carcinomas. In early stages (Tis-T1a), cholecystectomy alone can cure the disease and for T2-T3, liver resection and lymphadenectomy is indicated¹⁰. Prognosis of Adenosquamous carcinoma is worse than conventional adenocarcinoma of gallbladder because of early direct invasion of adjacent organs such as liver and duodenum etc. Survival rate is approximately 16% and most of the patients succumb to disease within 6-7 months of diagnosis¹¹.
Adenosquamous carcinoma of gallbladder is a rare entity which presents like cholilithiasis. Its behavior is more aggressive than adenocarcinoma of gallbladder and it is locally more invasive.
Because of its rarity, limited literature is available about its clinicopathological behavior and treatment options. Such case reports can provide more detailed information and insight for further research.
There were certain limitations regarding this case as we could not follow up the patient for further treatment and prognosis.

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