Pleomorphic Carcinoma of the Colon: Morphological and Immunohistochemical Findings

Abstract

Pleomorphic carcinoma is an aggressive neoplasm defined by the World Health Organization (WHO) as a poorly differentiated (squamous cell carcinoma or adenocarcinoma) or undifferentiated carcinoma in which at least 10% spindle and/or giant cells are identified, or as a carcinoma constituted purely of spindle and giant cells. Although this entity has initially been shown in the lung, it has been described also in extrapulmonary locations, with only one report for a colonic site. A 65-year-old woman developed a caecal tumour. Gross examination revealed an endophytic/ulcerative mass 7 cm in length. Microscopically, the tumour was a poorly differentiated adenocarcinoma with a pleomorphic component that occupied more than 10% of the specimen. The tumour shared these histopathological findings with pulmonary giant cell carcinoma but differed in other clinicopathological features such as a pushing growth pattern, stage pT3N1, and an uneventful outcome 24 months after operation. The pleomorphic component showed morphological and immunohistochemical features compatible with mitotic catastrophe, a non-apoptotic cell death occurring in cycling cells after aberrant mitosis. These features included multinucleation, micronucleation, atypical mitoses, foci of geographic necrosis, as well as immunohistochemical overexpression of p53 and Ki-67. The interpretation of the pleomorphic component as morphological expression of mitotic catastrophe may be useful in comprehending the pathogenesis of this rare neoplasm, and it may have practical implications as a potential cancer therapeutic target.

Morphology and Molecular Features of Rare Colorectal Carcinoma Histotypes

“…Pleomorphic adenocarcinoma (PlC) was firstly described in the colon in 1989 [101] with the report of two cases, and thereafter only a further two cases have been reported [102,103].…”

“…Age of presentation ranges between 67 and 86 years; three patients with pleomorphic CRC were females and one was a male [101,102,103].…”

“…Two cases involved the caecum, one was diagnosed in the descending colon and one in the sigmoid colon [101,102,103].…”

“…Although two patients with pleomorphic carcinoma were reported to have short survival [101,102], no definitive conclusions on the prognostic value of this variant can be drawn due to its rarity.…”

Severe Abdominal Pain Due To Gastrointestinal Obstruction in Patient With Lung Adenosquamous Metastases in Colon

“…Lung adenocarcinoma rarely metastasizes to the colon. 2,[5][6][7][8] Initially, the patient was suspected of having two different types of cancer. The lung biopsy result indicated squamous cell, while the ceccum showed adenosquamous.…”