Acta chir belg, 2006, 106, 92-95
Toe Leiomyoma A Case Report with Radiological Correlation N. Turhan-Haktanir*, A. Haktanir**, Y. Demir*, Ç. Tokyol***, M. Acar** Departments of Plastic and Reconstructive Surgery*, of Radiology** and of Pathology***, Afyon Kocatepe University Medical Faculty, Afyon, Turkey.
Key words. Leiomyoma ; Magnetic Resonance Imaging ; toe. Abstract. Only a limited number of case reports concerning the magnetic resonance imaging appearance of lower extremity leiomyoma have been published. To the best of our knowledge, there is not any instance of toe leiomyoma reported with MRI findings. We present MRI findings of a toe leiomyoma and discuss the literature.
Introduction Smooth muscle tumours of soft tissue are relatively rare tumours. It is estimated that leiomyomas of soft tissue account for 3.8% of benign soft tissue tumours (1). Thus the collective experience relative to these lesions in soft tissue is extremely limited in comparison with the literature related to gastrointestinal and uterine smooth muscle tumours. The majority of these tumours are located in the gastrointestinal tract, lungs, liver and adrenal glands. Leiomyoma in foot has rarely been reported in the literature. The tumour has a predilection for middle-aged females, is often associated with pain, and lies usually subcutaneously within a well-defined capsule. Only a limited number of case reports concerning the magnetic resonance imaging (MRI) appearance of lower extremity leiomyoma have been published (2). To the best of our knowledge, these is no instance of toe leiomyoma reported with MRI findings. We present MRI findings of a toe leiomyoma and discuss the literature.
Fig. 1 The tumour mass can be seen in the inferior aspect of right toe. The overlying skin is not thinned or discoloured.
Case report A healthy 44-year old man with no antecedent trauma, presented with a 2-month history of a slowly growing mass in the inferior aspect of right toe. He could not wear his right shoe comfortably and at times, suffered from pain. He did not complain of tenderness. The mass was semi-mobile and hard, and was located in the subcutaneous tissue. The overlying skin was not thinned or discoloured (Fig. 1). Laboratory investigations disclosed no abnormality. In the anamnesis of the patient, he suffered from ancyklosing spondylitis for 15 years, though he had not any clinical manifestation. Ultrasound examination revealed 22 20 mm, non homogeneous hypoechoic, solid mass. MRI showed a
well-demarcated, subcutaneous soft tissue mass over the tendon of flexor hallucis longus. The soft tissue mass had heterogeneous high signal intensity on T2-weighted Gradient Echo MR images. On T1-weighted Spin Echo MR images curvilinear signal void lesions were noted within the slightly hyperintens mass. After administration of contrast agent, homogeneous contrast enhancement was evident within the mass on T1-weighted images (Fig. 2). Tumour resection was performed, a well-circumscribed mass was identified in the subcutaneous tissue and over the flexor hallucis longus tendon. No invasion of adjacent tendon was present. The resected specimen measured 2.5 2.0 cm in size and was richly vascularized
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Fig. 2 MR images of the lesion : a soft tissue mass having heterogeneous high signal intensity on T2-weighted Gradient Echo MR images (upper left) ; T1-weighted Spin Echo MR images in coronal (upper right) and axial (lower left) planes, showing curvilinear signal void lesions within the mass, and contrast enhanced T1 MR image in coronal plane, demonstrating evident homogeneous enhancement (lower right).
(Fig. 3). Microscopic examination revealed spindleshaped cells arranged in fascicles, and the tumour showed positive immunohistochemical staining for smooth muscle actin and desmin. No significant cellular pleomorphism of mitotic activity was noted (Fig. 4). The pathological diagnosis was solid type of vascular leiomyoma. Clinical follow-up evidenced no local recurrence nor distant metastasis. Discussion Leiomyoma is a benign smooth muscle neoplasm that frequently occurs in extra-skeletal sites including ovaries, uterus, bladder, lung and gastrointestinal tract. Sometimes the skin and subcutaneous soft tissues are involved, as in vascular leiomyoma arising from the small blood vessels of smooth muscle. The tumour arises rarely from the periosteal membrane or from bone. Vascular leiomyoma usually occurs as a solitary
Fig. 3 The excised specimen measuring 2.5 2.0 cm
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Fig. 4 Histopathological examination of the lesion showing a nodular lesion located in the deep dermis of skin tissue (top, HE 4) ; well demarcated tumoral lesion formed by spindle-shaped cells arranged in fascicles (middle, HE 10) and the rich vascularization of the lesion (bottom).
subcutaneous lesion, with a predilection for the lower extremities of middle-aged women (2-6). The pathogenesis is unclear. Tumour mass is the most frequent complaint from the patients (3). If the tumour is located in the feet, fitting on shoes may be a problem (3). Pain, with or whitout tenderness, exists in approximately 60% of the patients (4). The most reliable treatment for vascular leiomyoma is
N. Turhan-Haktanir et al. the total excision of the lesion (3). Although the majority of these tumours are small, ranging from 0.5 to 2 cm in diameter, they freuqnetly grow larger (3, 5). Vascular leiomyomas arise commonly in the deep layers of the dermis, or in the subcutaneous tissue (3). The tumour is generally rounded, forming a nodule that usually elevates the skin (5). They are histologically classified as solid, cavernous or venous (4). Microscopically, the solid type of vascular leiomyoma is composed of intersecting smooth muscle bundles originating from medium sized vessels that lack elastic fibers (7). The presence of curvilinear signal void lesions in MRI as in our case, is suggestive of tortuous muscular vascular channels surrounded by smooth muscle bundles. The bulk of the tumour is composed of smooth muscle and fibrous tissue (3). Areas of myxoid change and hyalinization are sometimes present (4). It is probable that loose cellularity with oedematous change tends to cause prolongation of relaxation time in T2-weighted MR imaging. The heterogeneity of signal intensity in the tumour on Gradient Echo T2-weighted MR images is compatible with these histological appearances. Vascular leiomyoma are benign soft tissue lesions that should be included in the differential diagnosis of any pedal soft tissue mass. There should be an increased index of suspicion for vascular leiomyoma, especially when a freely movable subcutaneous mass is encountered in a middle-aged female patient. Schwannoma, or also called neurilemoma, often occurs in the flexor surface of the lower extremities, showing a well demarcated mass of high signal intensity on T2-weighted MR images (8). However, prominent tortuous structures of signal void may suggest the diagnosis of vascular leiomyoma. Vascular leiomyoma must also be differentiated from fibroma, lipoma, ganglionic cyst, glomus tumour, leiomyosarcoma and phlebitis. Vascular leiomyoma should be kept in mind when vascular structures are noted on MR examination of a well demarcated soft tissue mass arising in the subcutaneous tissue of lower extremities. References 1. MYHRE-JENSEN O. A consecutive 7-year series of 1331 benign soft tissue tumors : clinicopathologic date : comparison with sarcomas. Acta Orthop Scand, 1981, 52 : 287-93. 2. KINOSHITA T., ISHII K., ABE Y., NAGANUMA H. Angiomyoma of the lower extremity : MR findings. Skeletal Radiol, 1997, 26 : 443-5. 3. DUHIG J. T., PATH D., AYER J. P. Vascular leiomyoma : a study of 61 cases. Arch Pathol, 1959, 68 : 424-30. 4. HACHISUGA T., HASHIMOTO H., ENJOJI M. Angioleiomyoma : a clinicopathologic reappraisal of 562 cases. Cancer, 1984, 54 : 126-30. 5. STOUT A. P. Solitary cuteneous and subcutaneous leiomyoma. Am J Cancer, 1937, 29 : 435-69. 6. FREEDMAN A. M., MELAND N. B. Angioleiomyomas of the extremities : report of a case and review of the Mayo Cvlinic experience. Plast Reconstr Surg, 1989, 83 : 328-31.
Toe Leiomyoma 7. ROSAI J. Soft Tissue. In : ROSAI J. (ed.). Ackerman’s durgical pathology, 7th ed. St Louis : Mosby, 1989, pp. 1547-633. 8. CEROFOLINI E., LANDI A., DE SANTIS G., MEIORANA A., CANOSSI G., ROMAGNOLI R. MR of benign peripheral nerve sheath tumors. J Comput Assist Tomogr, 1991, 15 : 593-7.
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