Myoepithelial Carcinoma of the Paracecal Mesentery: Aggressive Behavior of a Rare Neoplasm at an Unusual Anatomic Site

Abstract

Myoepithelial tumors of the soft tissues represent a rare group of neoplasms that vary in their clinical behavior, pathologic features and genetics. They are histopathologically typified by a myoepithelial immunohistochemical phenotype, of expression of one or more epithelial markers, S100 protein and smooth muscle actin. Because of their rarity and occurrence over a wide age range and at a variety of anatomic sites, they can be difficult to diagnose due to the lack of familiarity by physicians, which is compounded by their spectrum of histologic features and morphologic overlap with several other neoplasms. Recent genetic insights have aided classification, and it is increasingly understood that soft tissue myoepithelial neoplasms can be stratified into two distinct morphologic and genetic subgroups. We describe a case of a 44-year-old man who was diagnosed with a primary myoepithelial neoplasm of the paracecal mesentery, which showed aggressive local recurrence after four years. The tumor was composed of cords of ovoid cells within chondromyxoid stroma, and displayed a characteristic pancytokeratin, S100 protein and smooth muscle actin-positive myoepithelial immunoprofile. Primary myoepithelioma has not been previously described at this site, and this case highlights this varied family of tumors, emphasizes the need to consider myoepithelial tumor in the differential diagnoses of carcinoma variants occurring in the bowel or mesentery, and also adds to the number of reported myoepithelial neoplasms showing markedly aggressive behavior.

Abdominal myoepithelial carcinoma: A rare abdominal wall entity of an uncommon tumor

“…Metastasis is commonly seen with these tumors. Nearly half of all diagnosed cases risk metastatic disease [1] , [5] , [18] . The most common site of metastasis is the lung, followed by lymph nodes, soft tissues and bone [1] .…”

A series Cases study of Carcinomas derived from myoepithelial cells in head and neck regions

“…CMCHNs have been observed in the gingiva, palate and tongue, larynx, parapharynx, nasopharynx, nasal cavity, nasal sinus, lacrimal gland, inferior temporal fossa, etc [17,18]. And literatures reported that approximately 75% of EMC [19,20] originated from the parotid gland, 10% from the submandibular gland, 10-15% from the salivary glands, and the remaining occurred in the palate, maxillary sinus, nasal cavity, trachea, and the root of the tongue.…”

Soft-Tissue Myoepithelioma of the Retroperitoneal Space Mimicking a Pancreatic Tumor: A Case Report and Literature Review

“…Pathology examination of STM is challenging owing to microscopical diversity in cell morphology and types of stroma [ 3 , 12 ]. However, several studies showed that well-circumscribed margins and multinodular growth of spindled and plasmacytoid cells with eccentric nuclei in myxoid, hyalinized or chondroid stroma could be hallmarks for this benign tumor [ 3 , 5 , 15 ].…”

“…Surgical resection with complete removal (R0 status) is a preferable treatment option of STM. Incomplete resection significantly increases risks of recurrence even in benign myoepitheliomas [ 3 , 12 ]. The vast majority of these tumors show a favorable prognosis and low incidence of distant metastases [ 3 , 15 ].…”

“…Rarely it occurs in soft tissues with predominant growth in head and neck, pelvic girdle and limbs, where it usually appears as a palpable subcutaneous or subfascial painful or painless mass [3,7]. There are few reported cases of non-typical sites like orbit, mediastinum, abdominal wall, mesentery and ovary [8][9][10][11][12]. Retroperitoneal space is an extremely uncommon localization for this tumor, described in single publications [13].…”