Intranodal palisaded myofibroblastoma of the axilla

Abstract

A 60‐year‐old woman was admitted to our hospital with a 5‐day history of jaundice. Laboratory tests revealed a total bilirubin of 7.6 mg/dL (normal: 0.20‐1.20 mg/dL). Thoracoabdominal com‐ puted tomography (CT) showed a 15 mm nodular lesion within the duodenal papilla as well as an enlarged lymph node in the left axilla. Preliminary diagnosis was an ampullary neoplasm (confirmed at sur‐ gery) with left axillary metastasis. US of the left axilla was performed showing a 18 mm hypoechoic nodular lesion (Figure 1) suggestive of metastatic lymphadenop‐ athy. Color‐Doppler US demonstrated sparse vessels inside the nodular lesion (Figure 2). Mammography was normal. As axillary dissemination of an ampullary neoplasm is a rare event, US‐guided 14‐gauge needle biopsy of the lymphadenopathy was performed to rule out axillary node metastases with occult primary breast cancer and a diagnosis of intranodal palisaded myofibroblastoma (IPM) was made. Intranodal palisaded myofibroblastoma was first described by several authors in 1989. This benign and rare mesenchymal neo‐ plasm usually arises in inguinal lymphatic nodes from differenti‐ ated smooth muscle cells and myofibroblasts. It is characterized by the proliferation of hemosiderine‐laden histiocytes, spindle cells, and amianthoid fibers inside a lymph node. Other lymphatic locations include mediastinal or submandibular and less commonly retroperitoneum and axilla. The histogenesis of this lesion remains unclear, but it is thought to arise from (a) stromal cells with myoid features which are found in greater concentrations in inguinal lymph nodes, which could explain its higher incidence at this site