Abstract
Background/Aim: Angioleiomyoma is a benign, pericytic (perivascular) neoplasm that most frequently arises in the dermis or subcutis of the lower extremities. Extensive calcification is extremely uncommon in this condition.
Case Report: An 80-year-old woman presented with a 20-year history of a slowly growing, painless mass in the dorsomedial aspect of the left great toe. Physical examination revealed a 2.5-cm, firm, mobile, non-tender mass. Radiographs showed a well-demarcated, densely calcified mass. Computed tomography confirmed the presence of a calcified lesion without bone involvement. Magnetic resonance imaging (MRI) exhibited a well-defined mass with intermediate signal intensity on T1-weightwed sequences and high signal intensity on T2-weighted sequences. Peripheral low signal intensity areas correlating to the calcified portion of the mass were also observed on both T1- and T2-weighted sequences. Contrast-enhanced MRI demonstrated intense, relatively homogeneous enhancement in the non-calcified portion of the mass. The patient underwent an excisional biopsy of the lesion. Histologically, the lesion is composed of bundles of bland, well-differentiated smooth muscle cells with small slit-like vascular channels. In addition, calcium crystal deposits surrounded by aggregates of epithelioid histiocytes and multinucleated giant cells were observed. The patient had no evidence of local recurrence at the latest follow-up.
Conclusion: This unique case provides valuable insights into the understanding and treatment of acral calcified angioleiomyoma. Knowledge of this peculiar neoplasm is important because it can mimic a variety of benign and malignant soft-tissue tumors.
Introduction
Angioleiomyoma, also known as vascular leiomyoma, is a distinctive benign soft-tissue tumor originating from the smooth muscle layer of blood vessels (1). According to the latest World Health Organization classification of soft-tissue tumors, it belongs to the group of pericytic (perivascular) tumors (2). Angioleiomyoma comprises about 4.4% of all benign soft-tissue tumors and 0.2% of all tumors of the foot and ankle (3). The etiology of this peculiar tumor is still unknown. Calcification can be observed in acral regions, so-called “acral calcified angioleiomyoma” (4-9) (Table I). Herein, we describe an unusual case of calcified angioleiomyoma involving the great toe in an elderly woman. We also provide a literature-based discussion of this rare condition. Written informed consent was obtained from the patient to publish this case report and accompanying images.
Main clinical features of patients with acral calcified angioleiomyoma.
Case Report
An 80-year-old woman presented with a 20-year history of a slowly growing, painless mass in the dorsomedial aspect of the left great toe. Her past medical history included osteoporosis and family history was noncontributory. Physical examination revealed a 2.5-cm, firm, mobile, non-tender mass (Figure 1). Neurovascular examinations were normal. Laboratory data were within normal limits. Radiographs revealed a well-demarcated, densely calcified mass (Figure 2). Computed tomography confirmed the presence of a calcified lesion without bone involvement (Figure 3). Magnetic resonance imaging (MRI) showed a well-defined mass with intermediate signal intensity on T1-weightwed sequences (Figure 4A) and high signal intensity on T2-weighted sequences (Figure 4B). Peripheral low signal intensity areas correlating to the calcified portion of the mass were also observed on both T1- and T2-weighted sequences. Contrast-enhanced fat-suppressed T1-weighted sequences exhibited intense, relatively homogeneous enhancement in the non-calcified portion of the mass (Figure 4C). Based on clinical and radiological features, we highly suspected the possibility of a benign calcified soft-tissue lesion such as tumoral calcinosis and calcifying aponeurotic fibroma.
Clinical photograph showing a soft-tissue mass in the dorsomedial aspect of the left great toe.
Plain radiographs demonstrate a well-demarcated, densely calcified mass in the metatarsophalangeal joint of the left great toe.
Conventional (A) and three-dimensional (B) computed tomography images exhibit the presence of a calcified lesion without osseous involvement.
Axial magnetic resonance images of acral calcified angioleiomyoma with intermediate signal intensity on T1-weighted sequence (A) and high signal intensity on T2-weighted sequence (B). Peripheral low signal intensity areas correlating to the calcified portion of the mass are also observed on both T1- and T2-weighted sequences. (C) Contrast-enhanced fat-suppressed T1-weighted sequence demonstrates intense, relatively homogeneous enhancement in the non-calcified portion of the mass.
An excisional biopsy was performed under general anesthesia with tourniquet control. A longitudinal incision was made on the dorsal side of the left great toe. The mass was adherent to the surrounding fibrous tissues; however, the mass was fully excised. No adjacent bone involvement was noted. Grossly, the excised mass was well-circumscribed, with a gray-white, gritty cut surface (Figure 5). Microscopically, the lesion consisted of bundles of bland, well-differentiated smooth muscle cells and intervening small slit-like vascular channels (Figure 6A). In addition, calcium crystal deposits surrounded by aggregates of epithelioid histiocytes and multinucleated giant cells were observed (Figure 6B). Nuclear atypia and mitotic figures were absent. Based on these findings, the pathological diagnosis was angioleiomyoma with tumoral calcinosis.
Gross appearance of angioleiomyoma displaying a well-circumscribed mass with a gray-white, gritty cut surface.
Histological features of angioleiomyoma. (A) The tumor is composed of bland, well-differentiated smooth muscle cells with intervening vascular channels. (B) Calcium crystal deposits surrounded by aggregates of epithelioid histiocytes and multinucleated giant cells can be seen.
The postoperative course was uneventful. There was no evidence of local recurrence at the 3-month follow-up.
Discussion
Angioleiomyoma has a peak incidence in the fourth to sixth decades of life, with a slight female predominance (10, 11). It typically presents as a solitary, small (usually less than 2 cm), firm, well-circumscribed, slow-growing, often painful, subcutaneous nodule (1). Angioleiomyoma shows a broad anatomic distribution but most frequently occurs in the lower extremities. Complete surgical excision is the treatment of choice for symptomatic angioleiomyoma, and prognosis is excellent. Malignant transformation in angioleiomyoma, usually into leiomyosarcoma, has been described (12, 13), but it is exceptionally rare.
Calcification is radiographically observed in 4.8-17% of cases (11, 14). Moreover, calcification can be detected on histological examination in 2-13% of cases (6, 10, 11). Acral calcified angioleiomyoma is a clinicopathological variant of angioleiomyoma (8). Clinically, acral calcified angioleiomyoma usually presents as a nondescript, often painful, tender nodule in the foot of middle-aged and elderly patients, with a longer history of duration (9, 15). The pathogenesis of acral calcified angioleiomyoma remains controversial. Some authors have suggested that minor repetitive trauma may play a role in the development of calcification (5, 9). In the current case, imaging modalities showed extensive calcification within the mass. Subsequently, histological examination confirmed the presence of extensive calcification and giant cell reaction simulating the tumoral calcinosis appearance. There were no abnormal laboratory findings or systemic conditions, suggesting a local problem. We speculate that intermittent subclinical minor injury may serve as an etiologic agent in our case. To the best of our knowledge, this is the second case of acral angioleiomyoma with histological features similar to conventional tumoral calcinosis.
Key imaging modalities of angioleiomyoma include ultrasonography (US) and MRI. US usually shows a round or oval-shaped, well-circumscribed hypoechoic mass with internal vascularity (14). In addition, a feeding vessel is sometimes observed (16). On MRI, the lesion is well-defined and displays isointense relative to skeletal muscle on T1-weighted sequences and hypertense relative to skeletal muscle on T2-weighted sequences (14). A dark reticular sign seems to be a characteristic feature of angioleiomyoma (1). A hypointense peripheral rim is found in 78.6% of cases (14). Marked homogeneous or heterogeneous enhancement is typically seen following intravenous contrast medium administration (14, 17). However, these imaging features are relatively non-specific and therefore histological examination is necessary for a definitive diagnosis of angioleiomyoma.
Based on vascular morphologies, angioleiomyoma is histologically divided into three subtypes: solid, venous and cavernous (1). Hachisuga et al. (10) reported that the solid subtype was the most common (66%), followed by the venous (23%) and cavernous (11%) subtypes. In the current case, the histological subtype was solid. A correlation between the tumor subtypes and the calcification appearance is unknown. Immunohistochemically, the tumor cells are positive for smooth muscle actin, muscle-specific actin, calponin and h-caldesmon and variably for desmin (18).
Conventional cytogenetic studies have demonstrated relatively simple karyotypes characterized by one or few chromosomal rearrangements or numerical aberrations (19-24). A t(4;5)(p12;q32-33) translocation is recurrent in angioleiomyoma (23, 24). This chromosomal translocation results in a cardiac mesoderm enhancer-associated non-coding RNA (CARMN)-TXK tyrosine kinase (TXK) gene fusion (24), leading to overexpression of TXK. Also, Xq22 rearrangement is a recurrent genetic event in angioleiomyoma (21, 24, 25), resulting in overexpression of insulin receptor substrate 4 (IRS4). Recently, notch receptor 2 (NOTCH2) rearrangements and mutations of platelet derived growth factor receptor beta (PDGFRB) and notch receptor 3 (NOTCH3) have been detected in a subset of angioleiomyomas (26, 27). Moreover, a recurrent somatic gap junction protein alpha 4 (GJA4) mutation has been identified in the cavernous subtype of dural angioleiomyoma (28).
Conclusion
Acral calcified angioleiomyoma is a distinct clinicopathological variant of angioleiomyoma that very seldom recurs after surgical excision. Angioleiomyoma should be considered in the differential diagnosis of subcutaneous calcified soft-tissue lesions of the foot, especially in middled-aged and elderly female patients.
Acknowledgements
The Authors are grateful to Dr. Yuichi Yamada for his expert opinion and valuable comments on the histological diagnosis of this case.
Footnotes
Authors’ Contributions
YS performed the operation and contributed to data collection. JN drafted the article. YC contributed to the discussion and reviewed the article. All Authors read and approved the final article.
Conflicts of Interest
The Authors declare no conflicts of interest associated with this article.
Artificial Intelligence (AI) Disclosure
No artificial intelligence (AI) tools, including large language models or machine learning software, were used in the preparation, analysis, or presentation of this article.
- Received September 17, 2025.
- Revision received October 7, 2025.
- Accepted October 23, 2025.
- Copyright © 2026 The Author(s). Published by the International Institute of Anticancer Research.
This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY-NC-ND) 4.0 international license (https://creativecommons.org/licenses/by-nc-nd/4.0).
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