A 31 y.o. woman presented a swelling on the plantar aspect of the 4th inter-metatarsal space. There was no history of direct trauma; she had first noticed this swelling about two months before. There was neither pain nor difficulty in movement. She was puerperal of three months.
A 31 y.o. woman presented a swelling in the distal end of the 4th inter-metatarsal space. Plain films didn’t show the presence of calcifications; there was initial bone involvement with a single extrinsic erosion and periostal reaction. Ultrasound examination of the soft-tissue mass revealed a solid hypo-echoic mass, clearly distinguished from normal structures. Color Doppler US images showed intense vascularization around and intra-lesion. In the MR examination T1-weighted spin-echo (SE), PD-weighted turbo-spin-echo (TSE), T2-weighted gradient echo (GE) and GE-STIR sequences were acquired, with scans on the axial, coronal and sagittal planes, followed by fat-sat T1-w post-contrast acquisitions. The solid mass was 3,0 x 2,4 x 2,4 mm in size; it extended from the 4th intercapitometatarsal space and involved the distal phalanx of the 4th finger. The lesion presented a polilobate border and appeared hyperintense in the high contrast sequences and with intense post-contrast enhancement. Histological examination stated it was an aggressive angiomyxoma with leiomiomatosis aspects.
Angiomyxoma (AM) is a rare benign soft-tissue tumor characterised by its myxoid and vascular components. Its compliant nature tends to grow to large size, displacing the adjacent structures, even if the tumor is usually locally infiltrated. AM is considered an aggressive neoplasm as it frequently tends to recur locally if not completely excised. But, due to the bulky and locally infiltrating nature of this tumor, a complete surgical excision is considered technically difficult. Having done the gross pathologic examination, AM appears as a large bulky and gelatinous mass, partially or completely encapsulated. Histologically, AM consists of spindle or stellate cells separated by a myxoid stroma with a large amount of fibroblasts, myofibroblasts, and variably sized vessels. Moreover, mitotic activity has been shown to be rare in the majority of cases. To summarise, surgical excision is the primary treatment for AM: although the tumor is histologically benign, locally aggressive behaviour and high recurrence rates require complete excision. Furthermore, as patients with AM demonstrate a low mitotic activity, radiation therapy or chemiotherapy is unlikely to have effect. What is highly recommended is a long-term follow-up with CT and, preferably, MR imaging, given that recurrences have been reported several years after first excision. The characteristics of angiomyxoma at the MR examination are: the tumor is isointense related to muscle on T1-weighted image, hyperintense on T2-w image and enhanced after gadolinium contrast with a typical internal pattern. The differential diagnosis includes myxoma, angiolipoma, lipoma and hemangioma. Soft-tissue lipoma demonstrate bright signal intensity on T1-w images and do not increase in signal intensity on T2 or fat-suppressed T2-w fast spin-echo sequences. On STIR images, the fat signal in these lesions is nulled. Lipoma do not show enhancement after intravenous injection of a paramagnetic material. Hemangiomas range from the cavernous type to the capillary type. Intra-muscular hemangiomas is associated with variable amounts of fat, smooth muscle, myxoid stroma, and hemosiderin. Hemangiomas demonstrate low to intermediate signal intensity on T1-w images and bright signal intensity on T2-w images. Because of paramagnetic effects, central haemorrhage with hemosiderin deposits or peripheral hemosiderin-laden macrophages demonstrate low signal intensity on T1 and T2-w images. Mixoma is poorly delimitated in the muscle. It demonstrate low intensity on T1-w images and high intensity on T2-w images, like to a cystic formation. Angiolipoma has an heterogeneous pattern on T1-w and T2-w images.
Angiomyxoma of the foot
According to the provided X-ray, color Doppler ultrasound, and MRI images of the foot, a soft tissue mass is observed on the plantar side of the 4th intermetatarsal space. The X-ray shows that the overall bone morphology is normal, with no obvious signs of bone destruction or fracture. The color Doppler image reveals relatively abundant local blood flow, suggesting the presence of a vascular component within the lesion. MRI shows that the lesion has an approximately isointense signal compared to muscle on T1-weighted images and a hyperintense signal on T2-weighted and fat-suppressed sequences. After contrast enhancement, there is marked enhancement with relatively clear lesion borders; however, there is some tendency for infiltration into the surrounding soft tissue. Overall, the imaging characteristics indicate both myxoid and vascular components.
Based on the patient’s age, the three-month postpartum history, and the imaging features, the following possibilities can be considered:
Taking into account the vascular and myxoid components, high T2 signal, marked contrast enhancement, and local infiltrative features, angiomyxoma most closely matches the overall imaging presentation.
Considering the patient’s clinical presentation (a painless plantar mass three months postpartum, with no history of significant trauma) and imaging examinations suggesting a lesion with abundant myxoid and vascular components and a strong local infiltrative nature, and pending further verification by histopathological examination (if available), the most likely diagnosis is angiomyxoma.
If there is still uncertainty, further tissue biopsy and immunohistochemical analysis are needed to exclude other rare or malignant soft tissue lesions.
Treatment Plan:
For angiomyxoma, complete surgical excision is the primary treatment approach. However, due to its local infiltration, defining the surgical margins precisely can be challenging, leading to a potential risk of recurrence. Radiation therapy and chemotherapy generally have limited effectiveness because of its low proliferative activity and relatively complex blood supply. Therefore:
Rehabilitation and Exercise Prescription:
During postoperative recovery or conservative observation, rehabilitation and exercise can be carried out as follows:
During the postpartum period, special attention must be paid to bone and joint stability. If there is a risk of osteoporosis, supplementation with calcium and vitamin D is recommended, and exercise safety must be ensured.
Disclaimer: This report is a reference analysis based on the information currently provided and does not replace an in-person consultation or professional medical advice. If you have any questions or if your condition changes, please seek medical attention promptly.
Angiomyxoma of the foot
