Glomus tumors (GTs) are mesenchymal tumor consisting of glomus cells originating from normal glomus, blood vessels, and smooth muscle cells [1]. Most GTs are benign and often occur in the skin of the head and neck, muscles, and distal limbs, the subungual region of the digits [2]. GT in the prostate is very uncommon finding, only one case of malignant prostate glomus tumor has been reported [3]. Currently, there are no reports on benign glomus tumors of the prostate, making this potentially the first case. An accurate diagnosis relies on pathological examination.

Histologically, GTs are usually well-circumscribed nodules comprised of uniform round cells with centrally located nuclei and well-defined cell borders [2]. GTs are subdivided into solid glomus tumor, glomangioma, and glomangiomyoma. 75% of cases are solid glomus tumor, with poor vasculature and scant smooth muscle component. Glomangioma, the second most common type (20%), has a prominent vascular component. Glomangiomyoma are the rarest type, with prominent vascular and smooth muscle components [4, 5]. Due to the fact that glomus bodies are specialized neurovascular organs of the skin, tumors are most commonly located in the deep dermis or subcutaneous tissue of the limbs involved in temperature regulation [4]. They arise in regions abundant in glomus bodies, such as the subungual areas of the digits or the deep dermis of the palm, wrist, forearm, and foot [2]. Nevertheless, a few of case reports indicate that glomus tumors can arise from sites where glomus bodies are absent, such as the mediastinum, penis, nerves and bones [5, 6], and also including the prostate, which is highlighted in this case report. It has been proposed that some GTs might be induced by the differentiation of pluripotent mesenchymal cells or ordinary smooth muscle [5]. IHC staining is valuable for diagnosing glomus tumors and distinguishing them from other conditions, as glomus tumor cells are stain-positive for type IV collagen, vimentin, h-caldesmon, calponin and smooth muscle actin, while the results for desmin, AE1/AE3, and S-100 proteins are usually negative [7,8,9].

Radiological examination can effectively assess the tumor’s location, size, extent of invasion, and distant metastasis. However, the MR Imaging features of GT are nonspecific and can also be found in other tumors like prostate cancer, extra-gastrointestinal stromal tumor (EGIST), neuroendocrine tumors, and hemangioma. Prostate cancer, the most prevalent malignancy of the prostate, typically originates in the peripheral zone of the prostate and is accompanied by a significant elevation in serum PSA levels. And the IHC markers such as P50, PSA, and PAP are positive [10]. Secondly, EGIST is a rare uncommon manifestation of gastrointestinal stromal tumors originating from the abdominal soft tissue [11]. CD117 and CD34 are highly sensitive IHC markers commonly used for diagnosing EGIST due to their similar pathological features and molecular biological characteristics with GIST [12]. Delay of germination 1 (DOG1) has higher specificity and sensitivity in the diagnosis of EGIST, and it is often used as the final diagnostic marker in cases with unclear tumor cell morphology [13]. Third is the neuroendocrine tumors, which is another rare and highly aggressive malignant tumor. Patients with neuroendocrine carcinoma typically show low levels of serum PSA and demonstrate limited responsiveness to endocrine therapy [14]. Early-stage disease may present with distant metastasis and paraneoplastic syndrome [15]. Immunohistochemical analysis showing positive expression of neuron-specific enolase (NSE), chromogranin a (Cga), and synuclein (Syn) plays a crucial role in diagnosing neuroendocrine carcinoma [9]. Hemangioma of the bladder or posterior urethra presenting with hematuria, hemospermia or urethral bleeding have been sporadically reported [16, 17]. Hemangioma arising in prostatic tissue causing lower urinary tract symptoms without hematuria or hemospermia is extremely rare [18].

The primary treatment for GT is surgical operation. Since the tumors are non-encapsulated and may exhibit irregular borders, there is a risk of recurrence if the nodule is incompletely excised. Large case series show recurrence rates after complete excision ranging from 0–6.6% [19]. But as described in our case, endoscopic resection is also an option for GT occurring in the prostate [20]. However, it is also important to consider the location and malignant potential of the tumor when deciding between surgical and endoscopic resection. [6]. Similar to other treatment options for prostate tumors, transurethral resection may be an effective method for GTs of the prostate. Completely resected small tumors without necrosis and mitosis have a favorable prognosis. However, due to the potential for malignancy, long-term follow-up and monitoring are strongly recommended [13].