Angiomyofibroblastoma of the mediastinum: A case report and literature review

Angiomyofibroblastoma and Potential Mimicking Soft Tissue Tumors That May Occasionally Present in the Retroperitoneum: An Approach to the Differential Diagnosis With Report of an Unusual Index Case Abutting the Kidney

The retroperitoneal soft tissues, extending from the pelvic floor to the level of the diaphragm, are the source of a variety of mesenchymal neoplasms with overlapping features and distinct clinical behaviors, making their distinction of crucial importance. Herein, we report a rare retroperitoneal angiomyofibroblastoma (AMFB) that presented as a right abdominal mass in a 25-year-old woman and that clinically simulated a primary renal carcinoma. The patient underwent complete surgical resection showing a well-circumscribed tumor adjacent to but separate from the right kidney. It was comprised of irregular, often anastomosing islands and cords of plump to spindled cells in a collagenous stroma with numerous thin-walled vessels. The tumor cells clustered around the vessels and admixed with moderate numbers of adipocytes. There was neither significant nuclear atypia nor mitotic activity. Immunohistochemically, the tumor cells showed strong reactivity for desmin, diffuse expression of estrogen and progesterone receptors, retained nuclear expression of retinoblastoma protein, and absent CD34 expression. The immunomorphological features were these of a "lipomatous variant" of AMFB of the retroperitoneum. The occurrence of AMFB in the retroperitoneum is unexpected since it mostly develops in the lower genital tract of young women, making its recognition in this rare location difficult. As a consequence, more common pelvic or retroperitoneal soft tissue neoplasms may represent the primary diagnostic considerations. We, therefore, review a variety of soft tissue tumors occurring in the pelvis/retroperitoneum that, to some degree, may mimic AMFB, and present key findings to assist in accurate diagnosis.

Angiomyofibroblastoma mimicking an inguinal hernia: a challenging diagnosis in a male patient

INTRODUCTION

Angiomyofibroblastoma is a rare benign myofibroblastic neoplasm which mainly occurs in the soft tissues of the pelvi-perineal region of females.

AIM

To present an unusual case of angiomyofibroblastoma mimicking an inguinal hernia in a 62-year-old male.

MATERIAL AND METHODS

The patient was hospitalized with an irreducible, painless inguinal mass and surgical intervention for inguinal hernia was decided. The well-defined nodular mass was sent for histological examination.

RESULTS

Under microscope, proliferation of spindle and oval cells around thin-walled vessels was observed, being intermingled with mature adipocytes. We did not identify necrosis, haemorrhage, cytologic atypia or mitotic figures. The tumour cells displayed positivity for desmin, vimentin, CD34, oestrogen and progesterone receptors, a low Ki67 index and unusual nuclear positivity for c-theta (PKCθ). They were negative for smooth muscle actin (SMA), S100, CD44, maspin, synaptophysin, DOG1 and CD117. The case was diagnosed as angiomyofibroblastoma, the main challenge being the differential diagnosis with aggressive angiomyxoma, which can present a similar histologic aspect and immunophenotype and recurs more frequently. No recurrences were observed 8 months after the surgery.

CONCLUSIONS

Angiomyofibroblastoma should be included in the differential diagnosis of inguinal hernia. This is the fourteenth case of angiomyofibroblastoma diagnosed in males.