Primary glomus tumor of the thymus in a 66-year-old patient.

We report a unique case of a 66-year-old man who was incidentally identified to have a mass in the thymus region by computerized tomography scan. CT revealed a well-defined 1.6 × 1 × 0.9 cm thymus mass with moderate uniform enhancement. Thoracoscopic thymectomy was performed, and the pathological diagnosis was primary glomus tumor of the thymus. There were no atypia or malignant histological features, and no primary tumors in other sites. To our knowledge, this is the first case of primary thymic glomus tumor reported in the literature.

Neurofibroma with glomus-like bodies: A novel association-Thoughts about origin.

A neurofibroma with focal glomus-like body differentiation is an unusual phenomenon recently encountered in an excision specimen from the right lateral distal forearm of a 26-year-old man. Glomus cells are modified smooth muscle cells normally present in glomus-like bodies but can also be found in glomus tumors (GT) or lesions considered in the spectrum of GT, including myopericytoma, myofibroma, and angiolipoma. Neurofibromas are peripheral nerve sheath tumors derived from the neural crest cells. While both GT and its variants and neurofibroma are thought to be derived from different cell types, there is growing evidence that glomus cells have a neural crest origin. This is based on multiple theories, with some overlapping pathways, including neural crest cell differentiation, Schwann cell reprogramming, VEGF expression, and NF1 gene biallelic inactivation. This report adds to the growing evidence of possible neural crest origin for glomus cells and would help explain finding glomus-like bodies scattered through a neurofibroma.

Outcomes of the Transungual Approach in 56 Consecutive Digital Subungual Glomus Tumours.

Background: Glomus tumour is a painful small tumour of the glomus body commonly located under the nail bed. The aim of this study is to evaluate the correlation of clinical diagnosis with MRI findings, determine the prevalence of the tumour at different subungual locations and determine the differences in outcomes (if any) between a longitudinal and a transverse nail bed incision for excision of the tumour. Methods: This retrospective study of 56 subungual glomus tumour was conducted from May 2010 to December 2021. Data with regard to gender, age at presentation, digit involved, presenting symptoms, duration of symptoms, clinical signs, need for MRI, anatomical location, surgical approach (longitudinal versus transverse), histopathology result, period of follow-up and complications were recorded. Results: All 56 (100%) patients presented with classic triad of symptoms. The average duration of symptoms was 52.9 months (range: 3-204 months). Eleven (20%) tumours were in the sterile matrix, 38 (68%) at the junction of sterile and germinal matrix and 7 (12%) in the germinal matrix. The tumours were excised through the longitudinal incision in 31 (55.3%) patients and transverse incision in 25 (44.7%). One (1.8%) tumour was intraosseous that was diagnosed intraoperatively and excised successfully. Average follow-up was 35.4 months (range: 6-120 months). There was no difference in outcomes (pain or nail deformity) between the two incisions. One patient (1.8%) has persistent pain that was due to a missed satellite lesion in the same digit. This was excised later with resolution of symptoms. There were no recurrences and all patients were cured after excision of tumour. Conclusions: Diagnosis of glomus tumour is usually clinical, and most are located at junction of sterile and germinal matrix. Tumour can be excised either by longitudinal or transverse nail bed incisions without any change of treatment outcome. Level of Evidence: Level IV (Therapeutic).

Tumor glómico causante de dolor de dedo crónico: la prueba de detección de isquemia es un signo clínico fiable para su diagnóstico. Informe de un caso y revisión de la literatura / Glomus tumor causing chronic finger pain: Ischemia test is a reliable clinical sign for the diagnosis. Case report and review of literature

Los tumores glómicos (TG) son neoplasias benignas raras, que se derivan de la estructura neuroarterial denominada cuerpo glómico, un shunt arteriovenoso especializado implicado en la regulación de la temperatura. Representan menos de 2% de los tumores del tejido blando, y entre 1 y 4,5% de los tumores de la mano. Aun cuando sus primeras descripciones aparecieron hace casi 100 años, son comunes la demora y la ausencia diagnósticas, las cuales originan un sufrimiento terrible. La tríada diagnóstica clásica consiste en dolor espontáneo, sensación de presión y sensibilidad, e hipersensibilidad al frío. La imagen de resonancia magnética (IRM) sigue siendo la modalidad de imagen más útil. La supresión del dolor tras inflar un esfigmomanómetro por encima de los niveles de la presión arterial sistólica (prueba de detección de isquemia) es altamente diagnóstica, por lo que sugerimos el uso rutinario de esta prueba simple en los casos de dolor en la extremidad superior de etiología desconocida. La resección quirúrgica es el tratamiento de elección, y es curativa. (AU)

Glomus tumors are a rare benign neoplasm arising from the neuroarterial structure called the glomus body, a specialized arteriovenous shunt involved in temperature regulation. They represent less than 2% of soft tissue tumors and between 1 and 4.5% of hand's tumors. Even though its first descriptions appeared almost 100 years ago, late and missed diagnoses are common, which leads to terrible suffering. The classic diagnostic triad consists of spontaneous pain, pressure sensation and tenderness, and cold hypersensitivity. Magnetic resonance imaging stills the most useful imaging modality. Abolition of pain after inflating a blood pressure cuff above systolic blood pressure levels (ischemia test) is highly diagnostic, so we suggest the routine use of this simple test in cases of upper limb pain of unknown etiology clear. Surgical excision is the treatment of choice and is curative. (AU)

Loss-of-function variants in GLMN are associated with generalized skin hyperpigmentation with or without glomuvenous malformation.

BACKGROUND: Inherited hyperpigmented skin disorders comprise a group of entities with considerable clinical and genetic heterogenicity. The genetic basis of a majority of these disorders remains to be elucidated. OBJECTIVES: This study aimed to identify the underlying gene for an unclarified disorder of autosomal-dominant generalized skin hyperpigmentation with or without glomuvenous malformation. METHODS: Whole-exome sequencing was performed in five unrelated families with autosomal-dominant generalized skin hyperpigmentation. Variants were confirmed using Sanger sequencing and a minigene assay was employed to evaluate the splicing alteration. Immunofluorescence and transmission electron microscopy (TEM) were used to determine the quantity of melanocytes and melanosomes in hyperpigmented skin lesions. GLMN knockdown by small interfering RNA assays was performed in human MNT-1 cells to examine melanin concentration and the underlying molecular mechanism. RESULTS: We identified five variants in GLMN in five unrelated families, including c.995_996insAACA(p.Ser333Thrfs*11), c.632 + 4delA, c.1470_1473dup(p.Thr492fs*12), c.1319G > A(p.Trp440*) and c.1613_1614insTA(Thr540*). The minigene assay confirmed that the c.632 + 4delA mutant resulted in abolishment of the canonical donor splice site. Although the number of melanocytes remained unchanged in skin lesions, as demonstrated by immunofluorescent staining of tyrosinase and premelanosome protein, TEM revealed an increased number of melanosomes in the skin lesion of a patient. The GLMN knockdown MNT-1 cells demonstrated a higher melanin concentration, a higher proportion of stage III and IV melanosomes, upregulation of microphthalmia-associated transcription factor and tyrosinase, and downregulation of phosphorylated p70S6 K vs. mock-transfected cells. CONCLUSIONS: We found that loss-of-function variants in GLMN are associated with generalized skin hyperpigmentation with or without glomuvenous malformation. Our study implicates a potential role of glomulin in human skin melanogenesis, in addition to vascular morphogenesis.

A group of skin conditions known as 'inherited hyperpigmented skin disorders' includes some diseases with different clinical and genetic traits. The genetic basis of the majority of these diseases is not understood. To identify the gene responsible for a disease that causes darker patches of skin (hyperpigmentation) with or without the abnormal growth of blood vessels and the presence of cells named glomus cells (a glomuvenous malformation), we used genetic techniques called whole-exome sequencing and Sanger sequencing in five unrelated families with this disease. We also used a technique called a 'minigene assay' to evaluate genetic alterations in a gene called GLMN, which encodes a protein called glomulin. Immunofluorescence and transmission electron microscopy (TEM) were used to determine the number of pigment-producing cells (called melanocytes) and melanosomes (where the pigment melanin is synthesized, stored and transported) in hyperpigmented skin lesions. We identified five different variants of the GLMN gene in five unrelated families. Although the number of melanocytes remained unchanged in skin lesions, TEM revealed an increased number of melanosomes. By 'switching off' the GLMN gene, we found that skin cells produced more pigment, as well as the proteins MITF and tyrosinase; they also showed a decrease in the phosphorylated protein p-p70S6 K. Overall, we found that loss-of-function mutations in GLMN caused skin hyperpigmentation with or without abnormal blood vessels. The results suggest there could be a potential role of the protein glomulin in human skin colour and blood vessel changes.

Nail-preserving excision of glomus tumor in the second toe: Case report and literature review.

INTRODUCTION: This case report describes the diagnosis of a glomus tumor in the second toe of a 38-year-old female, followed by surgical treatment utilizing a transungual approach to preserve the nail. This study highlights the diagnostic challenges and surgical strategies to treat such tumors while preserving nail integrity. PATIENT CONCERNS: Pain occurred once a week, but over time, it increased, and just before seeking medical attention, she experienced pain more than 5 times a day. The pain worsened when cold water touched her toe. DIAGNOSIS: We observed a slight hump indicating nail plate deformity, and the patient exhibited severe pinpoint tenderness (positive Love test) in the affected area. Color duplex ultrasound was performed for further investigation, revealing a hypervascular hypoechoic nodule measuring 0.5 cm in size at the nail bed of the right second toe. INTERVENTION: The surgery was performed under digital nerve block anesthesia using a modified transungual nail-preserving approach for the excision of the glomus tumor. OUTCOMES: The pain that was reported prior to the surgery has improved postoperatively, and the recovery has been uneventful without any other complication. CONCLUSION: This paper provides a comprehensive examination of a rare glomus tumor in the second toe, elucidating both diagnostic intricacies and treatment modalities. It emphasizes the dual necessity of achieving total tumor excision while also considering aesthetic outcomes. The insights presented herein are intended to serve as valuable guidance for clinicians confronted with similar clinical scenarios, underlining the delicate interplay between effective tumor management and the preservation of cosmetic integrity.

Glomus tumor causing chronic finger pain: ischemia test is a reliable clinical sign for the diagnosis. Case report and review of literature.

Glomus tumors are a rare, benign neoplasm arising from the neuroarterial structure known as the glomus body, which is a specialized arteriovenous shunt involved in temperature regulation. They account for less than 2% of soft tissue tumors and between 1% and 4.5% of tumors in the hand.. Despite their first descriptions appearing almost 100 years ago, late and missed diagnoses are common, leading to significant suffering. The classic diagnostic triad includes spontaneous pain, a sensation of pressure and tenderness, and cold hypersensitivity. Magnetic resonance imaging remains the most useful imaging modality. The abolition of pain after inflating a blood pressure cuff above the systolic blood pressure level (ischemia test) is highly diagnostic.Therefore, we suggest the routine use of this simple test in cases of upper limb pain of unclear etiology . Surgical excision is the treatment of choice and is curative.

Outcomes Following Excision of Toe Glomus Tumors.

BACKGROUND: Glomus tumors are uncommon tumors and their occurrence in the foot is even less common. Glomus tumors of the toes are often missed, causing delays in diagnosis and treatment. We report an ambispective observational study of glomus tumors of the toes that were treated at our institution. METHODS: We reviewed the records of all the patients who underwent excision of toe glomus tumors in our department from January 2010 to September 2022. The follow-up data were collected from the outpatient records and by telephonic interview. Single Assessment Numeric Evaluation (SANE) score, Foot and Ankle Outcome Score (FAOS), and the Foot Function Index (FFI) were collected. RESULTS: Out of all the patients treated for glomus tumors, we found that 7 patients had glomus tumors of the toes. Of the 7 patients, 6 were women and 1 was a male. The mean follow-up of our patients was 66.4 months (range, 7-109 months). Of the 7 patients, 1 presented with recurrent glomus tumor 30 months following the primary operation, for which she underwent excision again, after which she was symptom free. Another patient who developed recurrent symptoms on telephonic interview refused any further treatment. Among the 6 patients who were symptom-free at follow-up (including the patient who underwent excision for the recurrent tumor), the median SANE score, and FFI were 99.5 (IQR, 96-100) and 0.5 (IQR, 0-2) respectively. The mean FAOS was 96 (SD, 3.3). CONCLUSION: Surgical excision of the subungual toe glomus tumors can be curative. Recurrence of toe glomus tumors was noted in 2 patients (29%), one of whom refused further surgery. Re-excision in the other patient resulted in complete resolution of symptoms. LEVEL OF EVIDENCE: Level III, ambispective observational study.

Radiotherapy and Anrotinib in Malignant Glomus Tumor of the Bladder: A Case Report and Literature Review.

Background: Malignant glomus tumors (MGTs) are rare malignancies, which grow rapidly and are aggressive. Surgical resection has been regarded as the standard management, but treatment options for those unresectable tumors are limited, resulting in a high recurrence rate and poor prognosis. Case Description: An 85-year-old man presented with gross hematuria and was diagnosed with MGTs of bladder. The patient achieved long-term local control after multimodal therapy comprising radiotherapy, iodine-125 seeds brachytherapy, transcatheter arterial chemoembolization, and antiangiogenic targeted therapy. Conclusion: MGTs occurring in the bladder are clinically rare and refractory. The case presented here highlights the importance of multidisciplinary diagnosis and treatment, providing evidence that radiotherapy and antiangiogenic therapy may play an important role in unresectable bladder MGT.

A 65-Year-Old Man Presenting to the Emergency Department with Gastric Hemorrhage Caused by a Glomus Tumor.

BACKGROUND Glomus tumor is a benign but rapidly growing mesenchymal tumor that is a rare in the gastrointestinal tract, can be locally invasive due to its rapid growth, and can result in perforation of a viscus. We report a 65-year-old man presenting as an emergency with gastric hemorrhage and gastric glomus tumor. CASE REPORT A 65-year-old man came to our hospital for a life-threatening upper digestive hemorrhage. The preoperative examinations (digestive endoscopy without sampling of biopsy fragments and contrast-enhanced computer tomography) led to the presumptive diagnosis of gastrointestinal stromal tumor. Wedge resection of the gastric wall was performed. The histopathological examinations revealed a proliferation of round-oval cells of medium size with a solid disposition and in nests. This proliferation dissected the muscular tunic and caused ulceration of the gastric mucosa. Immunohistochemical tests confirmed the diagnosis of glomus tumor and excluded other diagnoses (neuroendocrine tumor or gastrointestinal stromal tumor). The postoperative evolution was favorable, and at the time of discharge, the biochemical test values normalized. CONCLUSIONS Pathologists are faced with a challenging task due to the deceptive appearance that can be presented by such a rare tumor. Histopathological and immunohistochemical examinations are essential in achieving a precise diagnosis and assessing the biological potential of the glomus tumor. Even if it is a benign tumor, the clinical picture it causes can still be a major risk to the patient's life. Consequently, ensuring effective case management becomes crucial, as it requires a thorough comprehension of all conditions encompassed in the differential diagnosis.

En Bloc Excision and Bone Grafting for Monostotic Multiple Intraosseous Glomus Tumors of the Distal Phalanx: A Case Report.

CASE: Glomus tumors of the hand are rare tumors that occur predominantly in the subungual region. Though multicentric glomus tumors have been reported in the subungual region involving the nailbed, monostotic multiple intraosseous glomus tumors have not been reported so far. We report a case of a 36 year-old woman who presented with a 5-year history of intermittent thumb pain, aggravated with exposure to cold or pressure. A glomus tumor of the thumb was excised, but symptoms returned 3 months later. She ultimately underwent curettage with bone grafting of a recurrent glomus tumor at the same site, and has been free of symptoms for 1.5 years. CONCLUSION: Intraosseous glomus tumors may present as multiple synchronous lesions. This, to the best of our knowledge, is the first case report of monostotic multiple intraosseous glomus tumors.

Infiltrative fibrous lesion of the facial nerve mimicking a facial nerve tumor.

PURPOSE: To report three cases of facial nerve lesions that were clinically expected to be facial nerve tumors but showed fibrotic infiltration without any apparent signs of a specific tumor on histopathological findings. We also aimed to investigate the clinical characteristics of these cases. METHODS: Medical records of patients who underwent surgery for facial nerve lesions were reviewed. RESULTS: All three cases initially had House-Brackmann (HB) grade IV-V facial nerve palsy. On radiological imaging, schwannoma or glomus tumor originating from the facial nerve was suspected. All patients underwent complete surgical removal of the neoplasm followed by facial nerve reconstruction using the sural nerve. The lesions were histologically confirmed as infiltrative fibrous lesions without tumor cells. In two cases, facial nerve palsy improved to HB grade III by nine months post-surgery, and there were no signs of recurrence on follow-up MRI. The other case, after 1 year of follow-up, showed persistence of HB grade V facial nerve palsy without any evidence of recurrence. CONCLUSION: Fibrotic lesions of the facial nerve could mimic primary facial nerve tumors. Clinicians should consider this condition even when a facial nerve tumor is suspected.

Novel ATG7::RAF1 gene fusion in malignant glomus tumor.

Glomus tumors are classified as members of the perivascular myoid family of tumors. Nearly half of these show NOTCH-gene fusions and a smaller subset has BRAF V600E mutations. Here, we report a novel ATG7::RAF1 fusion in malignant glomus tumor occurring in a 40-year-old female which has not been reported in the malignant glomus tumor before. A 40-year-old female presented with a persistent lateral heel pain and an increase in the size of a mass along the lateral ankle for nearly 10 years. Resected specimen showed a well circumscribed lesion composed of spindled and epithelioid cells with moderate nuclear atypia and mitotic figures (7/10 high-power fields) including atypical forms without any necrosis, lymphovascular, or perineural invasion. The tumor was positive for smooth muscle actin, smooth muscle myosin heavy chain, H-caldesmon, collagen type IV, and discovered on gastronintestinal stromal tumors-1 but negative for AE1/3, desmin, S-100, CD34, and CD117. RNA sequencing showed presence of ATG7-RAF1 fusion. This fusion has not been reported in the malignant glomus tumor before. Future studies on larger cohorts are needed to ascertain the biological significance of these tumors with novel gene fusions.

High-frequency ultrasonography for subungual glomus tumor evaluation - imaging findings.

OBJECTIVE: This article aimed to describe the common imaging features of subungual glomus tumors. METHODS: The study involved data collected between January 2019 and December 2022. Twenty-three patients with a total of 31 glomus tumors underwent high-frequency ultrasound examinations with a 24-MHz probe. Two experienced radiologists independently evaluated the images, and only data from the more experienced radiologist were used for subsequent analyses. RESULTS: The average size of the tumors was 4.6 mm, and most of them appeared homogeneously hypoechogenic (90.3%). Bone remodeling of the distal phalanx was observed in 87.1% of cases, with an average axial circumference loss of 0.8 mm, indicating the slow and expansive growth of glomus tumors. Intense vascularization was found in 54.8% of cases on Doppler images, and the stalk sign, reflecting the vascular origin of the tumor, was present in 64.5% of cases. The most common clinical feature was pain, reported in 84.6% of cases, with a mean pain scale score of 7.0, indicating a negative impact on patients' lives despite being benign tumors. CONCLUSION: The study concludes that ultrasound evaluation is highly useful for diagnosing glomus tumors, especially when multiple findings, such as bone remodeling, hypervascularization, and the stalk sign, are present. This method allows for accurate diagnosis, observation of periungual structures, and proper surgical planning, ultimately reducing recurrence rates.

The clinicopathologic and immunohistochemical features of 60 cutaneous glomus tumor: a retrospective case series study.

BACKGROUND: Glomus Tumor (GT) are benign neoplasms that originate from mesenchymal cells. It presents as tenderness and cold allodynia in the digits, especially in the subungual region. There are a few studies that investigated the mechanism of pain. OBJECTIVES: To analyze the clinical-pathologic characteristics of GT and to identify the expression of IL-1ß, IL-6, and CGRP in it, further, to explore the possible mechanism of pain. METHODS: The clinical and pathological data of 60 GT patients were retrospectively analyzed. Tissue microarrays and immunohistochemistry were used to measure the expression of IL-1ß, IL-6 and CGRP. RESULTS: GT is more common in females and the ratio of male to was near to 1:2, mostly in middle-aged people. It often occurs in fingertips, especially the thumbs. Patients often present with spontaneous pain, tenderness, and cold hypersensitivity. Both the two pain mediators IL-1ß and IL-6 were highly expressed in GT cells of patients with and without cold hypersensitivity. While CGRP was not expressed in GT. STUDY LIMITATIONS: Low sample size and further research is needed to explore the specific mechanism. CONCLUSIONS: IL-1ß and IL-6 were highly expressed in GT cells, suggesting that IL-1ß and IL-6 have certain nociceptive roles in GT. In the 4 patients with cold intolerance, the intensity of IL-1ß and IL-6 staining was also strong, suggesting that they may not play a role in the cold hypersensitivity. However, since there are only 4 patients with cold intolerance, it's necessary to conduct further in-depth research using a larger sample size. The specific role of CGRP in GT has not been found yet.

A rare cause of AA amyloidosis: Glomus tumor and treatment with anakinra-Case report and literature review.

Systemic AA amyloidosis is associated with poorly controlled chronic inflammatory disorders. Chronic infections and inflammatory arthritis are the most common causes; however, they can also rarely occur as a complication of neoplastic disorders. The development of AA amyloidosis secondary to paraganglioma, which is a rare type of tumor, has rarely been reported in the literature. In this case, an 85-year-old female patient with a glomus tumor in the neck, who has been followed up over 50 years, applied with complaints of loss of appetite, nausea, and diarrhea for 5-6 months. While evaluating the patient, who had high levels of acute phase reactants, amyloidosis was diagnosed by salivary gland biopsy. No other cause was found to explain amyloidosis. The patient, who could not tolerate treatment with colchicine and azathioprine, is successfully treated with the interleukin-1 inhibitor anakinra. A rare relationship, systemic AA amyloidosis, which is thought to have developed as a result of long-standing jugular paraganglioma, is presented in this article. In addition, publications showing an association between paragangliomas and amyloidosis were reviewed.

A Rapidly Expanding Hemorrhagic BRAF-Mutant Orbital Atypical Glomus Tumor.

A healthy 32-year-old woman presented with the acute onset of left sided eye pain, upper eyelid fullness, and binocular diplopia during light weightlifting. Examination elevated intraocular pressure, proptosis, upper eyelid ptosis, and motility deficits. CT demonstrated a well-circumscribed, homogeneous-appearing extraconal mass in the superior left orbit. The patient underwent an urgent orbitotomy with the excision of a hemorrhagic mass. Histopathology showed a glomus tumor with atypical features and hemorrhagic infarction, best classified as having uncertain malignant potential. A B-Raf proto-oncogene V600E mutation was detected with immunohistochemistry, which suggests a more aggressive tumor behavior yet presents an opportunity for targeted primary or adjunctive therapy. This is the first reported case of a B-Raf proto-oncogene-mutant atypical glomus tumor arising in the orbit.

Mucosa-associated Lymphoid Tissue Misdiagnosis as Glomus Tympanicum.

Middle ear tumors are diverse, but relatively uncommon. The most frequent tumor in the middle ear is glomus tumor, followed by others such as schwannoma and cholesteatoma. We experienced a case of Mucosa-associated lymphoid tissue hyperplasia as a middle ear tumor. The mass behind tympanic membrane appeared a hypervascular tumor, mimicking a glomus tumor, but the form of multiple separate masses in middle ear and mastoid cavity was the distinguishing feature that set it apart from a glomus tumor. Additionally, another characteristic was its tendency to easily shrink under pressure. This characteristic should be considered when encounter a hypervascular looking middle ear mass. Laryngoscope, 134:1894-1896, 2024.

Malignant glomus tumor arising in association with a fumarate hydratase-deficient leiomyoma: An unusual collision tumor.

Collision tumors, defined as "two independent neoplasms that occur in close proximity to one another but maintain distinct boundaries," are quite rare. We report an exceptional collision tumor composed of a genetically confirmed malignant glomus tumor and a fumarate hydratase (FH)-deficient leiomyoma, presenting as a subcutaneous thigh mass in a 38-year-old male who was known to have hereditary leiomyomatosis and renal cell carcinoma syndrome. Microscopic examination identified a biphasic subcutaneous mass comprising sheets and nodules of glomus cells, with nuclear atypia and mitotic activity, and fascicles of mitotically inactive smooth muscle with variably pleomorphic nuclei and intracytoplasmic eosinophilic inclusions, features of FH-deficient leiomyoma. Immunohistochemistry demonstrated loss of FH and robust 2-succinocysteine expression in the smooth muscle, with a normal (FH-retained) expression pattern in the glomus tumor. Next-generation sequencing, performed on the glomus tumor component, identified CARMN::NOTCH2 fusion, characteristic of malignant glomus tumors. Awareness of the distinctive morphologic, immunohistochemical, and molecular genetic features of glomus tumors and FH-deficient leiomyomas is important for correct clinical management of patients with exceptional collision tumors of this type.