Background: Calcifying fibrous tumor (CFT) is a rare entity, with a distinctive histological presentation, initially reported as childhood fibrous tumor with psammoma bodies. It is a benign hypocellular fibrous neoplasm calcifications and lymphoplasmacytic infiltrate. The CFTs may involve many sites, including gastrointestinal tract, pleura, abdominal cavity, and neck. The diagnosis might be challenging due to histological overlaps with other mesenchymal tumors. The prognosis is good. We describe herein the case of a 53-year-old woman with an incidentally diagnosed CFT of the mesentery. Case presentation: A 53-year-old woman presented to the surgery department with a 2-year history of an anterior abdominal hernia. A computed tomographic scan of the abdomen failed to demonstrate any evidence of a mesenteric nodule. The patient underwent surgical treatment. Careful exploration during the excision of herniated sac revealed a solitary nodule of the mesentery. Local excision was performed. On gross, it was a well-demarcated nodule. Microscopically, the tumor consisted of an abundant paucicellular hyalinized collagen with calcifications; associated to a sparse mononuclear inflammatory infiltrate. Conclusions: Calcifying fibrous tumor is a benign lesion. The diagnosis is based on histology, because clinical and radiological features are nonspecific. Awareness of this entity is crucial to distinguish it from other mesenchymal tumors especially in the gastrointestinal tract.

Retroperitoneal leiomyomas are rare benign tumors with smooth muscle differentiation, with only ~1001 cases reported in the English literature to date. Because of its scarcity and non-specific presentation, the preoperative diagnosis might be challenging. On histology, these neoplasms share the same macroscopic, morphological and phenotypic features with uterine leiomyoma; thus, they are referred to as leiomyoma of gynecologic type. Herein, we describe a case of a voluminous retroperitoneal leiomyoma in a 51-year-old woman with a history of total hysterectomy to raise awareness about this condition, as its differential diagnosis might be challenging.

Hepatoid adenocarcinoma is a rare type of extrahepatic adenocarcinoma with glandular and hepatocyte differenciation. The tumor can occur in many organs, generally in the stomach, the location of the lung being extremely rare. Despite poor prognosis and few effective treatment options, a timely and accurate histopathological diagnosis is key to optimal clinical management for long-term survival. Given the few reports published to characterized hepatoid adenocarcinoma, the emergence of any new case will contribute to improve understanding of the disease. Very few reports have been published to characterize hepatoid adenocarcinoma cytologically or even histologically. The aim of this work is to focus on the anatomoclinical characteristics of this rare entity. We present a retrospective study of 2 cases of pulmonary hepatoid adenocarcinoma confirmed by histological and immunohistochemical study.

Adrenal sarcomatoid carcinoma (ASC) is a very rare aggressive variant of adrenocortical carcinoma showing carcinomatous and sarcomatous differentiation. It is a poorly differentiated carcinoma with poor prognosis. The diagnosis requires careful histological and immunohistochemical investigation. We describe a new case of ASC to raise awareness on this extremely rare entity. A 27-year-old woman presented with a right flank pain. Imaging revealed a tissular mass of the right adrenal gland without metastases. After adrenalectomy, histology revealed sheets of epithelioid cells that stained for synaptophysin and Melan-A; and spindled cells staining for S-100. We have reported the clinical and histopathological features of ACS’s case; as it is an extremely rare cancer with a challenging diagnosis. There is a need for a further understanding of ASC’s biology to improve it poor prognosis.

Osteosarcoma (OS) is the most common primary non hematopoietic malignant tumor of bone with a strict histologic definition: the presence of unequivocal osteoid produced by neoplastic cells. Rare variants displaying low-grade histological features have been described; among which chondromyxoid fibroma-like (CMF-OS) is the rarest. However, despite its bland morphology; CMF-like OS has an aggressive clinical behavior and a poor prognosis. To the best of our knowledge, only 3 cases of CMF-OS have been previously reported in children. Because of its atypicality and scarcity; misdiagnosis is more likely to occur. Herein we describe a new case of CMF-OS in a 13 years old girl with fatal outcome. Diagnosis was based on focal malignant bone formation and correlation with imaging studies. The aim of the present case presentation is to raise awareness of this rare entity and to highlight the challenging diagnosis