Epidermoid carcinoma of the pancreas has several similarities with adenocarcinoma but also some particularities, especially when it comes to evolution, since it is more aggressive, prognosis and also therapeutic management.

According to the new WHO classification of 2020, Epidermoid carcinoma is a subtype of ductal adenocarcinoma of the pancreas, the latter being part of the malignant tumors affecting this organ and also including ductal carcinomas, pancreatoblastomas and high-grade pseudo papillary solid tumors [2].

In a 2019 study of 114,166 cases of pancreatic cancer, only 356 cases had Epidermoid carcinoma (0.3%) [1]. Another study conducted in 2020 with a total of 73,074 cases compared adenocarcinoma cases with those with Epidermoid carcinoma of the pancreas, which constituted only 0.2% [3].

Explanatory theories have been proposed to explain the origin of these squamous cells. The diagnosis of a primary Epidermoid carcinoma of the pancreas is made only after eliminating the presence of an Epidermoid carcinoma located elsewhere, in particular the ENT sphere or the anal canal for example, but also eliminating an adenosquamous carcinoma which is characterized by a variable proportion of glandular cells and squamous cells which must constitute more than 30% of the tumor [4].

The normal pancreas is histologically devoid of epidermoid cells. However, benign squamous metaplasia has been noted in 9-64% of pancreases examined postmortem. Squamous metaplasia may be associated with chronic inflammation such as in chronic pancreatitis or pancreatic/biliary stenting. It is also identified in the adjacent ducts of 4% of pancreatic adenocarcinoma surgical specimens [5] and rarely in benign mucinous tumors of the pancreas [6]. It is suggested that these malignant squamous cells of the pancreas pass through various mechanisms, degeneration of a squamous metaplasia of the ductal epithelium, transformation of an adenosquamous tumor from which the adenocarcinomatous component has completely disappeared and differentiation with malignant transformation of the primitive multipotent cells [7,8]. The rarity of Epidermoid carcinoma of the pancreas has led many investigators to question whether it is really a distinct pathological entity, a primary pancreatic adenosquamous underdiagnosed as Epidermoid carcinoma or most likely a metastasis of a primary occult tumor [5,9].

Clinically and comparing with a study of 54 patients with Epidermoid carcinoma of the pancreas, the average age was 61.9 years vs. 67 years. Our patient reported a history of alcohol-smoking, in this study and among the 23 patients with a history of alcohol-smoking, 11 (47.8%) reported alcohol use, seven (30.4%) smoked, five (21.7%) both, while 10 (43.5%) reported no toxic habit. A large majority presented with pain (77.8%) and weight loss (57.4%), while 15 patients (27.8%) presented with jaundice. On diagnostic imaging findings, the average size of the tumor was 6.9 cm vs 4.5 cm, among these 51 cases, more than half (52.9%) the lesion were located in the head of the pancreas, the case also of our patient, three (5.9%) in the body, 11 (21.6%) in the tail and 10 (19.6%) in multiple locations. Biologically, 11 out of 40 (27.5%) had normal blood test values and tumor markers in 16/21 patients (76.2%) were within normal limits, unlike our patient who had a disturbed biological workup, notably a biological cholestasis syndrome, hyperleukocytosis which may be part of the paraneoplastic syndrome and also a very high CA 19.9 which is more or less specific to the pancreas [10]. In another study of 356 cases of Epidermoid carcinoma of the pancreas, the average age was 68.3 years, 55.9% were male, the tumor was located in the head in 54.4% of cases with an average size of 5.7 cm. The tumor was classified as stage III or IV in 71.8% of the cases, while only 28.2% were classified as stage I or II at diagnosis (the case of our patient) [1].

Surgically, the tumor was resectable in only 31.5% of the cases [10], this is explained by the delay in diagnosis but also the proximity of vessels whose invasion contraindicates surgery, the case of our patient who presented an envelopment of the superior mesenteric vein in 1/3 of its circumference without visible endoluminal bud.

The therapeutic course of action is still not codified. In general, the prognosis is poor, several studies have been performed evaluating the efficacy of surgical treatment, chemotherapy, radiotherapy or their combinations. In a study of a total of 155 cases of Epidermoid carcinoma, the median survival of patients who received surgical treatment was much higher than those who did not (21.3 vs. 6.8 months) [11]. Katz et al. reported that the use of radio-chemotherapy could improve prognosis in the palliative, but not adjuvant setting [12]. During this time no chemotherapy protocol has been proven to be effective to date.

The choice of surgical treatment in our case instead of endoscopic treatment given the lack of means and resources in developing countries and the lack of easy access to care, as well as the surgical option is associated with less recurrence of jaundice and postoperative readmissions but the problem that it has more postoperative mortality [13].