CASE 15057 Published on 24.10.2017

Recurrence of malignant phyllodes tumour in subcutaneous tissues of abdominal wall

Section

Breast imaging

Case Type

Clinical Cases

Authors

Olga Shaw, Jordana McAllister

Ulster Hospital; Upper Newtownards Road BT16 1RH Belfast
Patient

73 years, female

Categories
Area of Interest Abdominal wall ; Imaging Technique Ultrasound, CT
Clinical History
A 73-year-old woman presents with a palpable mass in the left iliac fossa. She has a past medical history of malignant phyllodes tumour in the left breast in 2003 (treated by mastectomy) and recurrence in the left axilla in 2012 and 2015 (treated by excision and axillary node clearance respectively).
Imaging Findings
A targeted ultrasound of the site of the patient's concern demonstrated a well-circumscribed and oval-shaped mass with lobulated borders, measuring 36 x 25 mm, in the subcutaneous soft tissues of the abdominal wall in the left iliac fossa. The mass is heterogeneous, but predominately hypoechoic (Fig. 1). The mass is not invading the overlying skin or underlying abdominal wall muscle (Fig. 1, 2 and 3). Core biopsy of the mass was performed. Histology examination revealed a metastatic malignant phyllodes tumour. The patient underwent staging CT of the chest, abdomen and pelvis, and it did not identify further metastatic disease. The patient was treated by surgical excision of the mass. A consequent histology examination confirmed the metastasis of the malignant phyllodes tumour.
Discussion
Background
Phyllodes tumour (PT) of the breast is a rare fibroepithelial neoplasm, with an incidence of less than 1% of all breast neoplasms [1]. The spectrum of PT ranges from benign to borderline and malignant. Malignant PT comprises 20-25% of all PTs [3, 4], making it a rare histopathological entity. The rate of distant metastasis of malignant PT was reported as 9-27% [17].

Clinical Perspective
There are no specific clinical or radiological characteristics that enable reliable differentiation of benign and malignant PT [1, 5, 8]. Malignant tumours are often larger and faster growing, but size and growth rate are poor predictors of the histopathological type [1]. The triple assessment of the patients by clinical, radiological, and cytological or histological examinations forms the essential diagnostic pathway for all breast lesions.

Imaging Perspective
Mammography: PT appears as a dense mass, with circumscribed or lobulated margins. Partially indistinct borders favour malignant PT [2]. Malignant PT with osteosarcomatous differentiation is associated with intratumoral macrocalcifications. However, calcifications are generally rare in PTs because of their rapid growth [7].
Ultrasound breast: PT appears as a hypoechoic, round or oval mass, with circumscribed or lobulated borders, resembling fibroadenoma. Lobulation, heterogeneous hypoechoic internal echoes and absence of calcifications favour PT [9]. Intramural cystic areas are seen more often in malignant than in benign PT [2, 8, 9].
MRI breast: PTs are hypointense or isointense compared with adjacent breast tissue on T1-weighted images, and can be hyperintense or hypointense on T2-weighted images. Heterogeneous inner structure and internal septations are frequently seen in PTs. There may be increased T2 signal in the tissue surrounding PT [10, 11]. 33% of PT have contrast enhancement characteristics suggestive of malignancy [11].
CT: The primary tumour and metastases may appear as a heterogeneous enhancing mass [10].

Outcome
The 5-year overall survival rate is 84% and 5-year cause-specific survival is 91% for malignant PT after initial surgical management [4]. Tumour size and surgical margins are the principal determinants of local recurrence and distant metastasis [13]. Patient prognosis is extremely poor after metastatic spread [17].
Metastases of malignant PT spread mostly by the haematogenous route [17] to the lungs (most frequent site) [12], mediastinum, skeleton [3, 7], cardiac chambers [14, 15], kidney [16], brain, GI tract and uterus [17].

Take Home Message
There are no pathognomonic clinical or radiological characteristics that enable reliable identification of the malignant PT. Metastasis of malignant PT is rare, but has been reported to various organs of the body.
Differential Diagnosis List
Metastasis of malignant phyllodes tumour in the abdominal wall.
Metastasis of melanoma
Metastasis of lymphoma
Final Diagnosis
Metastasis of malignant phyllodes tumour in the abdominal wall.
Case information
URL: https://eurorad.org/case/15057
DOI: 10.1594/EURORAD/CASE.15057
ISSN: 1563-4086
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