Rhabdomyomatous mesenchymal hamartoma of the tongue

A systematic review of the clinicopathological characteristics of oral leiomyomatous hamartoma

BACKGROUND

Oral leiomyomatous hamartoma (OLH) corresponds to an abnormal, benign and disorganized overgrowth of mature smooth muscle tissue, which can develop in any site where this tissue is found in healthy conditions. The present systematic review aimed to analyze the clinicopathological characteristics of OLH.

MATERIALS AND METHODS

The protocol of this study was constructed following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) and was registered in the Open Science Framework (OSF): OSF.IO/BMPUX. Five electronic databases were used to identify studies for this systematic review: PubMed, Web of Science, Dentistry & Oral Science Source, Scopus and ScienceDirect, from January 15th, 1945 to January 10th, 2024. The Joanna Briggs Institute (JBI) tool was used to assess the risk of bias and the quality of the included reports and case series.

RESULTS

A comprehensive search yielded 5,562 articles, of which 55 met the inclusion criteria. The total number of subjects studied in the included investigations was sixty-six. The subjects' ages varied from newborns to 61 years, with a mean age ± standard deviation of 71.23 ± 123.01 months. 50.7% were males and 49.3% were females. Most lesions presented normochromic color (24.24%), pedunculated base (31.81%), firm consistency (22.72%), with an average size of 1.20 cm, present on the dorsum of the tongue (31.81%) or anterior part of the alveolar border of the maxilla (30.30%). Treatment was carried out by surgical excision (78.46%) and half of the studies report that there were no recurrences.

CONCLUSIONS

The cases described in the medical-dental literature provide valuable information to date on the clinicopathologic and immunohistochemical profile of OLH. Although it is a rare lesion, it should be considered as part of the differential diagnosis in newborns, infants, children and young adults with lingual and/or maxillary masses present in the midline.

Rhabdomyomatous Mesenchymal Hamartoma: Report of 4 Cases With Histochemical and Immunohistochemical Findings and Emphasis on Potential Pitfalls

ABSTRACT

Rhabdomyomatous mesenchymal hamartoma (RMH) typically presents as a congenital midline head and neck cutaneous polyp in infants. Perianal and mucocutaneous lesions have been reported, and recently, acquired adult-onset variants have been proposed. This makes the true prevalence, etiopathogenesis, and clinicopathologic distribution and classification of RMHs in children compared with those in adults uncertain. We performed a retrospective review to highlight the salient histopathologic, histochemical, and immunohistochemical features in RMHs and to emphasize their specific clinicopathologic criteria to avoid diagnostic pitfalls. We found 4 (0.3%) infants [2 female infants and 2 male infants, average age: 4 months] with mental, nasal, lingual, and perianal midline RMHs (average size: 1.0 cm) of 1303 patients with cutaneous polypoid lesions. Three were isolated, and 1 was associated with Goldenhar syndrome. The cutaneous polyps demonstrated intermixed skeletal muscle, adipose, and fibrocollagenous core stroma that extended into the dermis and around the dermal appendages. The lingual lesion demonstrated skeletal muscle and fibrocollagenous stroma with prominent nerve bundles and little adipose tissue. All showed interstitial loose mesenchyme. Masson trichome demarcated the triphasic stromal components. Alcian blue demonstrated the loose myxoid mesenchyme. Elastic van Gieson did not show elastic fibers. Desmin demonstrated the skeletal muscle bundles, S100 highlighted the adipose tissue lobules and the nerve bundles, and CD34 displayed the mesenchymal stroma. Ki67 showed a low proliferation index in the loose mesenchyme. Smooth muscle actin did not reveal smooth muscle bundles, but with CD31, they highlighted the thick blood vessels. CD117 revealed prominent mast cells. From our retrospective review series, 4 cases that originally diagnosed as RMHs were excluded. Likewise, we found some examples of the reported cases in the English literature that might have been mistaken for RMHs. This is because they did not fulfill the diagnostic clinicopathologic criteria. RMH constitutes a rare entity with specific clinicopathologic features. Most lesions are isolated. Some are associated with congenital anomalies and syndromes. Strict clinicopathologic diagnostic criteria should be applied to avoid mislabeling look-alike lesions for RMHs.

Tongue hamartomas in pediatric patients: an international case series and literature review

This study reports 9 additional tongue hamartomas in children paired with a literature review. A retrospective analysis was performed from 3 Oral Pathology laboratories. Additionally, a literature review was conducted through 5 electronic databases and gray literature. A total of 9 cases were identified in the retrospective analysis. Females outnumbered males with a ratio of 1.25:1. The age of presentation ranged from 2 weeks to 7 years. The posterior dorsum tongue was the most affected subsite (n = 4). One case was seen in a patient with oro-facial-digital syndrome, 2 cases in patients with cleft palates, and one case with an encephalocele. The most common predominant component was salivary gland tissue (n = 4). A literature search included 79 pediatric patients presenting with 95 tongue hamartomas. A slight female (n = 47) predilection was observed, with ages varying from 15 hours to 19 years. The posterior tongue dorsum (n = 31) was the most affected site. Seven cases were seen in association with syndromes. The most common predominant component was smooth muscle (n = 35). Although hamartomas are rare in the oral cavity, they should be considered in the differential diagnosis of masses involving the posterior tongue dorsum in children.

Congenital Midline Tongue Base Mass in An Infant: Lingual Hamartoma

Lingual hamartoma is a rare finding of congenital midline posterior tongue mass. The lesion may be seen as a single anomaly or maybe associated with syndrome especially the Oral Facial Digital Syndrome (OFDS). Here, we report an otherwise normal and healthy two-month-old boy with a congenital midline base of tongue mass presented with snoring and episodic vomiting since the age of 1 month. Tumour excision from the area of foramen of caecum recovered a pinkish pedunculated tumour. Histopathology examination confirmed the diagnosis of leiomyomatous lingual hamartoma. Differential diagnosis, especially for midline tongue mass and other paediatric tongue lesions are discussed. We also discuss the epidemiology, histopathologic features, treatment and prognosis of lingual hamartoma based on the literature review.

Biopsy-proven spontaneous regression of a rhabdomyomatous mesenchymal hamartoma

Rhabdomyomatous mesenchymal hamartoma (RMH) is a rare, benign, congenital tumor of the dermis and subcutaneous tissue comprised of skeletal muscle and adipose and adnexal elements. Although the majority of cases are an incidental finding in otherwise healthy patients, some have been reported in association with other anomalies. We present a full-term boy evaluated on day 2 of life for two lesions located on the midline of the lower back and right buttock that each appeared clinically as an atrophic, pink plaque. Ultrasound of the midline lesion revealed an underlying lipomyelomeningocele with a tethered cord in the spinal canal. Histopathology of the right buttock cutaneous lesion was consistent with a diagnosis of RMH. Surgical excision was performed on the midline intradural lipoma and the lesion on the buttock was monitored clinically. Repeat biopsy of this site at 1 year of age revealed complete spontaneous regression. This case highlights three interesting features: the association with an occult spinal dysraphism lipomyelomeningocele and tethered cord, the clinical presentation of an atrophic plaque as opposed to the more commonly reported raised lesions, and the phenomenon of spontaneous regression of the lesion. Most importantly, this final feature of regression in our patient suggests that, in the absence of symptoms, clinical observation of RMH lesions is warranted for spontaneous regression for 1 to 2 years provided that no functional deficit is noted and that the cutaneous or deeper lesions are not causing a medical problem.