Recurrent paratesticular aggressive angiomyxoma in an elderly patient: a rare case report

Abstract

Aggressive angiomyxoma is a rare benign mesenchymal tumor with local infiltrative potential and a high risk of local recurrence. Its occurrence in the paratesticular region is exceptional. We report the case of an 86-year-old male patient, with no significant past medical history, managed in our Urology Department for a recurrent paratesticular aggressive angiomyxoma. The patient underwent surgery three times for successive local recurrences, which were histologically confirmed. The current evolution is marked by a small, asymptomatic local recurrence under surveillance. This case illustrates the diagnostic difficulty, the complex surgical management, and the importance of prolonged follow-up for this rare entity.

Introduction

Aggressive angiomyxoma (AAM) is a rare, benign soft-tissue mesenchymal tumor, first described by Steeper and Rosai in 1983 [1]. It is typically found in the pelvic and perineal regions, predominantly affecting adult women during their reproductive years [1]. AAM is extremely rare in men, with fewer than 100 male cases reported in the literature to date; recent systematic reviews have identified only 85–97 male cases worldwide [2, 3]. In males, the most common site is the scrotum, while localizations in the paratesticular tissues (spermatic cord, epididymis) are considered exceptional [4–6]. These tumors are characterized by slow growth, significant local infiltration, and a high tendency for recurrence, which often presents a challenge for complete surgical management [7]. We present a rare case of a recurrent paratesticular AAM in an elderly patient.

Case report

An 86-year-old male presented to our urology department with a progressive, painless swelling of the right hemiscrotum lasting for 6 months. He had no significant personal or family medical history. Physical examination revealed a large, firm, non-tender, and non-transilluminating mass in the right scrotum, which was distinctly separate from the testis. No palpable inguinal lymphadenopathy was noted.

The initial tumor markers were within normal limits. A computed tomography (CT) scan revealed a paratesticular mass measuring 5 × 6 × 7 cm. The patient underwent a total local tumor excision. Intraoperatively, the surgeon noted an infiltrative, gelatinous mass adhering tightly to the surrounding scrotal tissues. Histopathological analysis of the resected specimen revealed a hypocellular tumor composed of bland spindle cells embedded in a prominent myxoid stroma, characterized by numerous thick-walled blood vessels infiltrating the adjacent soft tissues. On immunohistochemistry, the neoplastic cells showed diffuse positivity for vimentin, CD34, estrogen receptors (ER), and progesterone receptors (PR), while remaining entirely negative for S-100 protein. Additional immunohistochemical staining demonstrated positivity for desmin and smooth muscle actin (SMA). HMGA2 expression was also assessed and supported the diagnosis of aggressive angiomyxoma. This specific immunophenotype definitively confirmed the diagnosis of aggressive paratesticular angiomyxoma. The surgical margin status could not be reliably assessed because of the infiltrative growth pattern of the tumor and specimen fragmentation.

Despite complete macroscopic excision, the patient's clinical course was marked by three successive local recurrences, all confirmed histopathologically. The first recurrence, measuring 7 cm in diameter, was detected 10 months postoperatively during routine follow-up, and a repeat surgical excision was performed. Pathological examination again confirmed aggressive angiomyxoma; however, surgical margin status was not assessable. Nine months later, a second recurrence was identified; a CT scan showed a large, well-circumscribed, soft-tissue density mass occupying the paratesticular region, measuring 7 × 6 cm, occupying the midline, and extending anteriorly (Figs. 1 and 2). A wide local re-excision was performed (Fig. 3). Histopathological analysis confirmed a second recurrence of aggressive angiomyxoma, but margin status remained non-assessable. In all surgical procedures, the testis and spermatic cord were successfully preserved.

Fig. 1.

Coronal computed tomography scan showing large well-defined soft-tissue density mass occupying paratesticular region

Fig. 2.

Axial computed tomography scan showing very large, well-circumscribed mass located in the paratesticular region, occupying the midline and extending anteriorly

Fig. 3.

Postoperative appearance of the paratesticular mass (2nd recurrence)

One year later, a third recurrence was detected on surveillance imaging. Given the patient's advanced age, the burden of repeated surgical interventions, and the current small, asymptomatic nature of the lesion, the multidisciplinary team opted for active surveillance. At the latest follow-up 18 months later, the recurrence remained radiologically stable, and the patient was completely asymptomatic. The chronology of clinical events, surgical interventions, recurrences, and follow-up is summarized in Table 1.

Table 1.

Clinical timeline of recurrent paratesticular aggressive angiomyxoma

Time from initial surgery	Clinical event
0 months	Initial excision of 5 × 6 × 7 cm paratesticular AAM
10 months	First local recurrence (7 cm); repeat excision
19 months	Second local recurrence (7 × 6 cm); wide local re-excision
31 months	Third local recurrence detected on surveillance imaging: active surveillance chosen
49 months	Stable disease under active surveillance; asymptomatic patient

AAM Aggressive angiomyxoma

Discussion

Aggressive angiomyxoma is an extremely rare mesenchymal neoplasm in the male genitourinary tract, highlighting the importance of including it in the differential diagnosis of myxoid tumors in this region. The rarity of AAM in men is underscored by a 2022 systematic review reporting only 97 cases up to September 2020, and another review from 2022 finding only 85 male cases since the disease was first described in 1983 [3]. In our case, the paratesticular location is less common than the scrotum, which is the most frequent site in males, accounting for approximately 42.3% of cases [4].

While AAM is typically described in women of reproductive age, the mean age of presentation in males is around 48.2 years, with a peak incidence between 40 and 60 years [3]. Cases have been reported across a wide range, from a 10-month-old infant up to an 81-year-old patient [8]. Our patient, at 86 years old, represents an exceptional presentation in the context of advanced age, a factor that must be heavily weighed in the individualized management plan.

Angiomyxoma in the scrotum and paratesticular region usually presents as a slow-growing, painless mass. The clinical course is typically non-specific, often leading to a long history of asymptomatic swelling before a diagnosis is established. Scrotal ultrasonography is often the initial diagnostic modality and typically shows a hypoechoic lesion with well-defined margins. However, magnetic resonance imaging (MRI) is considered more effective for providing precise anatomical detail of local extension and infiltration due to its superior soft-tissue contrast [9]. MRI typically shows the tumor as hyperintense on T2-weighted images and isointense on T1-weighted images [9]. These features are crucial for differentiating angiomyxoma from other scrotal and paratesticular masses, such as hydroceles or myxoid sarcomas [9]. Although MRI represents the gold standard for evaluating the local extent of AAM [10], it was not performed in our patient, which constitutes a limitation of our report. Instead, computed tomography (CT) was utilized to detect and monitor the recurrences, primarily due to the patient's advanced age and his difficulty tolerating prolonged imaging procedures.

Regarding pathogenesis, the gross morphology, clinical progression, and histopathology of AAM in males resemble those seen in females. The diagnosis is confirmed by histology and immunohistochemistry (IHC), which remains the gold standard. The typical IHC profile for AAM is characterized by 100% positivity for Vimentin and positivity for CD34 (in 63.4% of cases). Consistent with this profile, the immunohistochemical analysis of our patient's tumor demonstrated positivity for both Vimentin and CD34. Crucially, AAM in males often expresses Estrogen Receptor (ER) (50% positive) and Progesterone Receptor (PR) (53.3% positive) [11]. Concordantly, our patient's specimen exhibited strong expression for both ER and PR. This hormonal receptor positivity is significant as it provides a potential rationale for adjunctive hormonal therapy [7]. The vast majority of cases (91%) are negative for S-100, which helps exclude other myxoid tumors; as expected, our patient’s tumor was strictly negative for S-100. In addition, our case demonstrated positivity for desmin and smooth muscle actin (SMA), findings that are frequently reported in aggressive angiomyxoma and further support its myofibroblastic differentiation. HMGA2 expression was also positive in our patient. HMGA2 overexpression has been recognized as a characteristic feature of aggressive angiomyxoma and represents a useful adjunctive marker for distinguishing this entity from other myxoid mesenchymal neoplasms with overlapping histopathological features. The combination of the characteristic morphology and the immunohistochemical profile, including positivity for vimentin, CD34, desmin, SMA, ER, PR, and HMGA2, strongly supported the diagnosis in our case.

The mainstay of treatment for AAM remains wide and complete surgical excision with negative tumor margins (R0) [2, 12]. In the systematic review of male AAM cases, wide and complete surgical excision was achieved in 72% of cases [3]. Despite being histologically benign, AAM is locally aggressive and infiltrates surrounding tissues. This makes achieving clear margins difficult, leading to a high propensity for local recurrence [7]. While the overall recurrence rate reported in a series of male paratesticular cases was approximately 9.09–11.8%, our patient's history of three successive recurrences within a short period highlights the extreme infiltrative nature of the disease, particularly in the confined paratesticular space [4]. An additional limitation in our case was the inability to reliably assess surgical margins on the pathological specimens because of the infiltrative growth pattern of the tumor and specimen fragmentation. Consequently, it remains difficult to determine whether the repeated recurrences resulted from residual microscopic disease or reflected the intrinsic tendency of aggressive angiomyxoma toward local relapse despite apparently complete excision.

Given the strong hormonal receptor expression characteristic of AAM, alternative or complementary treatment modalities particularly hormonal therapies represent a valuable therapeutic avenue. Neoadjuvant or adjuvant hormonal treatments using Gonadotropin-Releasing Hormone (GnRH) agonists, tamoxifen, or aromatase inhibitors have emerged as available options for unresectable or recurrent lesions [7, 11, 13]. In the specific context of our old patient, systemic hormonal therapy was explicitly considered by the multidisciplinary team as a non-invasive alternative to manage the multiple local recurrences. However, this option was ultimately deferred. When balancing the potential adverse effects and morbidity of systemic hormonal deprivation in a very elderly individual against the small, completely asymptomatic nature of his latest recurrence, active surveillance was deemed the safest and most appropriate strategy.

The median follow-up time in published male series is relatively short (around 24.5 months), whereas the tumor's recurrence can be exceptionally late. Thus, our case reinforces the imperative for long-term surveillance after surgical resection [3, 4]. In the elderly population, such as in our patient, the decision for re-intervention must be carefully balanced against the patient's overall health and quality of life, emphasizing the necessity of an individualized, multidisciplinary approach.

Conclusion

Aggressive angiomyxoma of the paratesticular region represents an exceptionally rare and locally infiltrative neoplasm within the male genitourinary tract. While diagnosis relies on characteristic histopathological features and a distinct immunohistochemical profile notably vimentin, ER, and PR positivity, its clinical management remains highly challenging. Despite multiple excisions, the development of three consecutive local recurrences in our elderly patient illustrates a significant therapeutic dilemma. Although surgery remains the primary treatment, prolonged multidisciplinary monitoring is crucial. Ultimately, this case confirms that active surveillance is a safe and pragmatic alternative to avoid the morbidity of repeated operations in the elderly population.

Author contributions

All authors have read and approved the manuscript for publishing. A. C, W.E, and I.A.M wrote the main manuscript text. M.G, N.R, and M.H.S prepared figures.

Funding

The authors declare that they have no funding sources.

Data availability

No datasets were generated or analyzed during the current study.

Declarations

Ethics approval and consent to participate

An informed consent was obtained from the patient. Approval was granted by Habib Bourguiba UNIVERSITY HOPITAL LOCAL ETHICS COMMITTEE (ID: 01060223) (Approval date: 12.12.2025).

Consent for publication

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

Competing interests

The authors declare no competing interests.