Right adductor compartment intramuscular myxoma: A rare case report

Abstract

Introduction

Extracardiac intramuscular myxomas are exceedingly rare benign tumors, necessitating well-planned management for optimal outcomes.

Case presentation

We report the case of a 63-year-old male with no prior medical history, presenting with a progressively enlarging mass within the adductor compartment of the right thigh. Physical examination revealed a mobile and painless mass measuring 70 mm by 50 mm at the level of the adductor compartment of the right thigh, devoid of signs of inflammation or skin lesions. The patient showed no cachexia, asthenia, or weight loss. Imaging exams confirmed the characteristic features of intramuscular myxoma, leading to the decision for complete surgical excision. Subsequent histological analysis confirmed the diagnosis, and the patient experienced no postoperative complications, showing positive long-term follow-up results.

Clinical discussion

In the presence of an intramuscular mass, thorough questioning and meticulous clinical examination enable us to propose a diagnosis of intramuscular myxoma. MRI is the preferred imaging modality, supporting diagnostic reasoning. However, histopathological analysis remains essential to confirm the mass's nature and rule out potential malignant differential diagnoses. Complete surgical resection is considered the gold standard, ensuring favorable results with a low risk of recurrence.

Conclusion

Extracardiac intramuscular myxomas are exceptionally rare; MRI and histopathological analysis combined help rule out potential malignant differential diagnoses. Total surgical excision yielded good results with a low risk of recurrence.

Highlights

• •Extracardiac intramuscular myxomas are extremely rare benign tumors.
• •Differential diagnoses are aggressive angiomyxoma, chondrosarcoma leiomyosarcoma, liposarcoma, and neurofibroma.
• •Finally, magnetic resonance imaging (MRI) is the gold standard for preoperative diagnosis.
• •Histological examination is crucial for confirming the diagnosis.
• •Surgical excision is the definitive treatment associated with a very low recurrence rate.

1. Introduction

In 1948, STOUT pioneered the characterization of myxomas, which are uncommon, benign tumors exhibiting low vascularity. These tumors comprise a myxoid stroma containing collagen and reticular fibers, encapsulating undifferentiated satellite cells [1]. The incidence of myxomas is limited, ranging from 0.1 to 0.13 per 100,000 individuals, particularly affecting those aged 40 to 60, with a heightened prevalence in women [[2], [3]]. Myxomas exhibit a size spectrum from 1.5 to 17 cm, and larger variants may present challenges in distinguishing them from sarcomas. While the thigh is the primary site, myxomas can also manifest in the upper arm, calf, and buttock [4].

Histological examination is crucial for confirming the diagnosis, and surgical excision is the definitive treatment associated with a very low recurrence rate [5].

Our case report adds to the existing body of knowledge by highlighting the novelty of the first reported case of intramuscular myxoma in Eastern Morocco. The tumor developed within the adductor compartment of the right thigh in a 63-year-old male; this case not only underscores the rarity of such occurrences but also emphasizes the importance of regional awareness and diagnosis for optimal patient care.

2. Case presentation

In accordance with the SCARE Criteria [6], we present the case of a 63-year-old male with no significant medical history who sought specialized medical management at the Department of Traumatology and Orthopedics for a mass located within the adductor compartment of the right thigh. According to the patient, the mass had progressively developed over five years with no associated symptoms; however, no measurements of its size were recorded, and the primary concern was its aesthetic appearance. The patient did not report cachexia, weight loss, or asthenia and did not receive any medication.

During the physical examination, a mobile and painless mass measuring 70 mm by 50 mm was observed at the level of the adductor compartment of the right thigh without signs of inflammation or skin lesions (Fig. 1). The right hip range of motion and neurovascular evaluation of the right lower limb revealed no abnormalities, and no lymphadenopathy was noted.

Fig. 1.

Clinical aspect of the mass in the inguinal region.

The MRI revealed an oval, well-defined mass measuring 53 × 38 × 57 mm (length × width × height) in the adductor compartment, with a positive cap sign (Fig. 2). After gadolinium injection, no contrast enhancement was observed, and the mass remained far from the ileofemoral vascular axis.

Fig. 2.

Sagittal T1 MRI view showing the mass with the bright cap sign.

The decision for surgical resection was made, and the same surgeon under general anesthesia in the supine position conducted the procedure. Following the administration of one gram of cefazolin, a direct approach was employed to dissect and reach the mass. The mass was then carefully released from its attachments using blunt dissection and electrocautery techniques, ultimately achieving complete resection (Fig. 3, Fig. 4). Histological examination confirmed the diagnosis of an intramuscular MYXOMA (Fig. 5, Fig. 6).

Fig. 3.

Complete surgical excision of the tumor.

Fig. 4.

Macroscopic appearance of the tumor after excision.

Fig. 5.

Microscopically, the lesion is composed of stellate and spindle-shaped cells embedded in an abundant myxoid stroma, containing thin collagen bundles and capillaries (HE, ×100).

Fig. 6.

At higher magnification, tumor cells are bland with no atypia or notable mitotic activity (HE, ×400).

Postoperative outcomes were favorable, and a four-year follow-up revealed no complications or signs of recurrence.

3. Discussion

Intramuscular myxomas are uncommon benign soft tissue tumors [1]. Virchow introduced the term «MYXOMA» in 1863 to describe tumors resembling the mucous tissue of the umbilical cord [7]. In 1948, STOUT provided a more detailed and precise histological description of these tumors as mesenchymal neoplasms composed of undifferentiated stellate cells embedded in a myxoid stroma containing weak reticular fibers [1]. Despite their potential association with mutations in the GNAS (guanine nucleotide-binding protein, alpha-stimulating) [8,9], the etiology of myxomas remains unknown [10].

These tumors typically manifest between the ages of 40 and 70, with a higher prevalence in females, accounting for 66 % of cases [11]. The extracardiac form can occur in various locations, with the thigh being the primary site in 51 % of cases, followed by the arm, calf, and buttock muscles [11].

Classical clinical evaluation reveals a painless, palpable mass with variable patterns depending on the size and site of the mass [12,13].

Several radiological modalities assist in diagnosis. Plain X-rays are often normal and rarely reveal the lesions as shading with calcifications in the soft tissue [[14], [15]]. Ultrasound typically shows a hypoechoic mass with occasional cystic components [5]. The CT scan of an intramuscular myxoma reveals a well-demarcated, homogeneous, low-density lesion within the substance of skeletal muscle [[5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16]]. Finally, magnetic resonance imaging (MRI) is the gold standard for preoperative diagnosis. Myxomas commonly appear as hypointense on T1-weighted MRI and hyperintense on T2-weighted MRI [17]. The presence of peritumoral fat visible on T1 with increased signal in the adjacent muscle on T2-weighted or fluid-sensitive MR sequences constitutes the most distinctive features of intramuscular myxomas. The frequent prominence of peritumoral fat at the superior and inferior poles of the tumor forms a specific radiological aspect referred to as the “Bright caps sign” [18].

No radiological evaluation alone can confirm the diagnosis, and histopathologic examination remains mandatory for diagnosis confirmation, as well as for ruling out differential diagnoses such as aggressive angiomyxoma, chondrosarcoma, embryonal rhabdomyosarcoma, leiomyoma, leiomyosarcoma, liposarcoma, and neurofibroma [19].

While the recurrence of these tumors is exceptionally rare, it should be regarded as a potential risk. Both preoperative and postoperative radiotherapy have not demonstrated proven benefits in the treatment of intramuscular myxomas [13]. Surgical resection remains the optimal treatment, and it is imperative to achieve complete excision of the lesion with clear margins to prevent local recurrences [16]. In some cases, extensive surgical resection may even be recommended [13].

4. Conclusion

Intramuscular myxomas are rare benign tumors, often asymptomatic. MRI is the radiological modality of choice, and histological analysis remains essential to establish the correct diagnosis and rule out malignant tumors. Surgical resection is the gold standard treatment to ensure clear margins whenever possible to avoid local recurrence, a rare but possible complication.

This case presentation significantly contributes to the medical literature by highlighting the novelty and uniqueness of the first reported instance of intramuscular myxoma in Eastern Morocco. While acknowledging the existence of similar cases in the literature, our case emphasizes the importance of regional awareness and diagnosis for optimal patient care. It expands our understanding of the epidemiology of myxomas.

Human subjects

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Consent

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Ethical approval

The ethical committee approval was not required give the article type. However, the written consent to publish the study was given and is available to check by the handling editor if needed.

Funding

None.

Author contribution

Taha El aissaoui: Study concept, Data collection, Data analysis, Writing the paper.

Adnane LACHKAR: Supervision and data validation.

Najib ABDELJAOUAD: Supervision and data validation.

Hicham YACOUBI: Supervision and data validation.

All authors read and approved the final manuscript.

Guarantor

Taha El aissaoui.

Research registration number

This is not an original research project involving human participants in an interventional or an observational study. This registration was not required.

Conflict of interest statement

In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work. This case has not been presented at a conference or regional meeting.