Skip to main content

Incidental Hamartoma in an elderly patient: a case report



Neuromuscular hamartoma is a very rare tumor; with only five cases reported in the orbit. It often occurs in infants and young children and involves large peripheral nerves, but there has been only few reports of occurrence in the orbit and adults.

Case presentation

This paper describes a 70-year-old man with an incidental orbital mass detected by an imaging test and who later developed associated symptoms. The mass was diagnosed as neuromuscular hamartoma. Superior rectus muscle recession and inferior rectus muscle resection were performed in the right eye for hypertropia secondary to postoperative inferior rectus muscle palsy. Hypertropia in the right eye and diplopia improved after surgery, and regular follow-up is underway.


This is the first case of an incidentally detected orbital mass diagnosed by histologic examination as a neuromuscular hamartoma in an older patient whose proptosis progressed after a long period of inactivity.

Peer Review reports


Neuromuscular hamartoma, also known as neuromuscular choristoma or benign triton tumor, is a rare benign tumor with well-differentiated, mature, striated muscle and nerve fibers [1]. In most cases, it involves large nerves, such as the brachial plexus or sciatic nerve [2], and typically appears in infants and young children. It is not common to find it in both the head and in adults [3].

According to a previously published report, there have been four neuromuscular hamartomas reported in adults and in the orbit [1, 3,4,5]. Therefore, we report a case of an orbital mass diagnosed as a neuromuscular hamartoma in an older male patient with proptosis.

Informed written consent was obtained from the patient for publication of this case report and accompanying images.

Case presentation

A 70-year-old man presented to the emergency department with sudden-onset chest discomfort and dizziness. Computed tomography (CT) scan revealed encephalomalacia in the right ventral frontal lobe with a mass in the superomedial aspect of the right orbit (Fig. 1). However, he had no ophthalmologic symptoms, and no specific treatment was administered for the mass.

Fig. 1
figure 1

Axial computed tomography scans show a homogenous well-enhanced mass (2.4 × 1.5 cm) at the superomedial aspect of the right orbit

Five years later, the patient presented to the neurology clinic complaining of headache. Magnetic resonance image (MRI) showed a solid mass (2.4 × 1.5 × 2.0 cm) at the superomedial aspect of the right orbit with T1 and T2 iso-signal intensity (Fig. 2). Comparison with a previous CT (Fig. 1) showed no change in the mass.

Fig. 2
figure 2

a T1-sagittal and b T1-axial, c T2-axial, and d T2-coronal magnetic resonance images reveal a solid mass (2.4 × 1.5 × 2.0 cm) at the superomedial aspect of the right orbit with T1 and T2 iso-signal intensity. There was no interval change in the mass compared with a previous CT

One month later, the patient presented to the ophthalmology clinic with right eye proptosis. On ophthalmologic examination, the degree of proptosis was 3 mm, but external ocular movement (EOM) was normal. A conservative management approach was decided based on the assumption of a benign mass. However, 2 years later, proptosis of the right eye had increased to 5 mm (Fig. 3), and signs of subconjunctival hemorrhage, chemosis, and downward ocular deviation of the right eye were noted in 9-cardinal photograph, but the EOM was normal (Fig. 4).

Fig. 3
figure 3

Photograph of proptosis of the patient’s right eye. The proptosis was 5 mm

Fig. 4
figure 4

A 9-cardinal photograph showed a subconjunctival hemorrhage, chemosis with proptosis of the right eye, and downward ocular deviation of the right eye, but the EOM was normal

One month later, an excisional biopsy was performed through a medial canthal incision to almost completely excise the brown-colored tissue. After incision, the thin capsulated mass was easily found and there was no adhesion with the surrounding tissue or rectus muscle, although it was difficult to remove completely due to bleeding. A histopathological evaluation of the tissue revealed a neuromuscular hamartoma with mature muscular tissue and proliferation of nerve tissue; the specimen was Desmin positive in muscle and S-100 positive in nerve tissue (Fig. 5).

Fig. 5
figure 5

Photomicrographs of the resected lesion. a Hematoxylin & eosin (H&E) staining shows mature muscular tissue (blue arrow) admixed with proliferation of nerve tissue (red arrow) (× 40). b Immunohistochemical staining for Desmin was positive in muscle tissue (blue arrow). (× 40) c Immunohistochemical staining for S-100 was positive in nerve tissue (red arrow) (× 40)

Postoperative steroid tapering was administered. At a follow-up visit on postoperative day five, the patient complained of vertical diplopia. Conservative management was applied because it was thought to be caused by conjunctival swelling over the inferior rectus muscle-side conjunctiva. Although exophthalmos and conjunctival swelling decreased, diplopia has worsened with EOM increased to 15 prism RHT and downward gaze limitation. Therefore, inferior rectus (IR) muscle resection (2 mm) & superior rectus (SR) muscle recession (3.5 mm) were performed based on diagnosis of inferior rectus muscle palsy (Fig. 6).

Fig. 6
figure 6

A 9-cardianl photograph showed abnormal ocular movement. In particular, downward gaze limitation was observed

Diplopia persisted after strabismus surgery, for which a prism glasses prescription was administered to relieve the symptom. Nearly, one year after strabismus surgery, The condition improved to around 4 to 6 prism RHT.


Finding neuromuscular hamartoma in the orbit is unusual; there have been only five reported cases [1, 3,4,5,6]. After a review of the literature (Table. 1), we believe this is the first case of this tumor occurring in an adult patient with age of 65 years and older [7,8,9,10,11,12,13] as it is known to mostly occur in infants and children [12, 13]. The proximal aspects of large peripheral nerves such as the brachial and sciatic nerves are most commonly involved with only a few cases involving the head and neck regions [10, 11, 13, 14]. One report found that this tumor is more likely to occur in women than men, with a 2.4 to 1 ratio [11].

Table 1 A literature review of neuromuscular hamartoma cases in the orbit

Neuromuscular hamartomas typically show moderate patchy enhancement with low or intermediate signal intensity on MRI [6] and are hyperattenuated on CT [9]. Lymphadenopathy is not seen. Simple moderate enhancement is not compatible with rhabdomyosarcoma, lymphoma, and nasopharyngeal carcinomas [15]. Because imaging features are not characteristic, neuromuscular hamartoma must be considered in the differential diagnosis of an orbital mass in a young child.

According to Daley et al. [10], neuromuscular hamartoma was divided based on the site of origin into two groups: an aggressive central type and a non-aggressive peripheral type. The central type invaded large intracranial nerves or infratemporal fossa nerve trunks, occasionally causing muscle atrophy and weakening. It most commonly extended to the infratemporal fossa via the foramen ovale by invading the fifth cranial nerve in or near the middle cranial fossa (specifically Meckel’s cave) [6, 9, 12, 13, 16]. These cases occurred in infants and children and required surgical treatment. The peripheral type was found in subcutaneous or submucosal tissues as non-encapsulated lumps and was asymptomatic, non-destructive, and slowly increased in size. This group of tumor was found in patients with older age, including adulthood [11, 14]. Surgical resection was simple and curable. Of the nine cases, five were central type, and four were peripheral type.

Clinical symptoms of neuromuscular hamartoma vary from asymptomatic to pain or neurologic deficit. Most tumors have no symptoms, but pain and neurological dysfunction such as paresthesia and muscle weakness, ophthalmoplegia, and migraine may occur depending on location [9, 12, 17].

Pathologically, the specimens were stained with hematoxylin and eosin and trichrome. Small nerve bundles and axons were seen intermixed with adjacent mature striated skeletal muscle bundles, surrounded by a dense collagenous matrix. The skeletal muscle noted to have small, bland, peripherally-placed nuclei with mature features and no cellular atypia or atypical mitoses. Immunohistochemically, S-100 and neurofilament stains showed normal nerve bundles. Desmin highlighted the hamartomatous striated muscle fibers intermingled with nerve bundles [18].

Treatment for neuromuscular hamartoma is excision for the aggressive central type and conservative management for the peripheral type. Incomplete excision can alleviate symptoms. Although most tumors have a good prognosis after resection, recurrence has been reported [11]. Therefore, physicians must closely follow patients after treatment. It is also important to preserve neural function during treatment, because nerve palsy may occur as a complication and is irreversible [8, 10, 19].

In the present case, the patient suffered from diplopia secondary to postoperative hypertropia in the affected eye. Although IR muscle resection & SR muscle recession were performed for correction, diplopia persisted for two months after strabismus surgery. It is thought that the inferior rectus muscle was paralyzed due to either compression by a retractor used to obtain a surgical field of view and control bleeding or direct damage during the operation. However, it is difficult to explain the precise mechanism as the tumor site was in the superomedial region.

The present case describes an orbital mass in the right eye of an elderly patient that was incidentally found in a head and neck imaging study. During follow up, proptosis progressed; thus surgical resection and biopsy were performed. Histological examination confirmed the mass as a neuromuscular hamartoma. This is the first case of an incidentally-discovered orbital mass that was diagnosed as neuromuscular hamartoma in an elderly patient whose proptosis progressed after a long period of inactivity.

Availability of data and materials

The datasets from the current study can be obtained on request from the corresponding author.



External ocular movement


Right hypertropia


Inferior rectus


Superior rectus


Hematoxylin & eosin


  1. Iferkhass S, Elkhoyaali A, Chatioui S, Elktaibi A, Elasri F, Reda K, et al. Neuromuscular hamartoma of the orbit: case report and discussion of the role of corticosteroids in treatment. J Fr Ophtalmol. 2015;38:112–7.

    Article  CAS  Google Scholar 

  2. Van Dorpe J, Sciot R, De Vos R, Uyttebroeck A, Stas M, Van Damme B. Neuromuscular choristoma (hamartoma) with smooth and striated muscle component: case report with immunohistochemical and ultrastructural analysis. Am J Surg Pathol. 1997;21:1090–5.

    Article  Google Scholar 

  3. Bae DH, Kim CH, Cheong JH, Kim JM. Adulthood benign triton tumor developed in the orbit. J Korean Neurosurg Soc. 2014;56:146–8.

    Article  CAS  Google Scholar 

  4. Cunniffe G, Fernández J, Alonso T, Balaguer O, Dinares C, Huguet P, et al. Thyroid Orbitopathy obscuring the diagnosis of a rare neuromuscular Hamartoma of the superior rectus muscle in an adult. Orbit. 2010;29(3):169–71.

    Article  Google Scholar 

  5. Perry A, Chan JW, Cotter JA, Bracha A. Intraorbital neuromuscular choristoma adjacent to the optic nerve. Human Pathol. 2017:1–3.

  6. Oeppen RS, Harden SP, Argent JD. Neuromuscular hamartoma: imaging features of a rare paediatric craniofacial tumour. Pediatr Radiol. 2003;33:50–2.

    Article  Google Scholar 

  7. Amita K, Shankar SV, Nischal KC, Basavaraj HB. Benign triton tumor: a rare entity in head and neck region. Korean J Pathol. 2013;47:74–6.

    Article  Google Scholar 

  8. Bonneau R, Brochu P. Neuromuscular choristoma. A clinicopathologic study of two cases. Am J Surg Pathol. 1983;7:521–8.

    Article  CAS  Google Scholar 

  9. Castro DE, Raghuram K, Phillips CD. Benign triton tumor of the trigeminal nerve. AJNR Am J Neuroradiol. 2005;26:967–9.

    PubMed  Google Scholar 

  10. Daley TD, Darling MR, Wehrli B. Benign triton tumor of the tongue. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2008;105:763–6.

    Article  Google Scholar 

  11. Demir Y, Uluoglu O, Ozmen S, Boyacioglu ZM, Atabay K. Neuromuscular hamartoma in the mental region. J Oral Maxillofac Surg. 2003;61:397–400.

    Article  Google Scholar 

  12. Tobias S, Kim CH, Sade B, Staugaitis SM, Lee JH. Neuromuscular hamartoma of the trigeminal nerve in an adult. Acta Neurochir. 2006;148:83–7.

    Article  CAS  Google Scholar 

  13. Tiffee JC, Barnes EL. Neuromuscular hamartomas of the head and neck. Arch Otolaryngol Head Neck Surg. 1998;124:212–6.

    Article  CAS  Google Scholar 

  14. O’Connell JX, Rosenberg AE. Multiple cutaneous neuromuscular choristomas. Am J Surg Pathol. 1990;14:93–6.

    Article  Google Scholar 

  15. Radzikowska J, Kukwa W, Kukwa A, Czarnecka A, Krzeski A. Rhabdomyosarcoma of the head and neck in children. Contemp Oncol (Pozn). 2015;19:98–107.

    CAS  Google Scholar 

  16. Vajramani G, Devi I, Santosh V, Hegde T, Das BS, Das S, et al. Benign triton tumor of the trigeminal nerve. Childs Nerv Syst. 1999;15:140–4.

    Article  CAS  Google Scholar 

  17. Akimoto J, Fukami S, Hashimoto R, Haraoka J. Neuromuscular hamartoma is a possible primary pathology of oculomotor ophthalmoplegic migraine. Cephalalgia. 2012;32:171–4.

    Article  Google Scholar 

  18. Lam S, Grandhi R, Wong R, Hamilton R, Greene S. Neuromuscular hamartoma of the sciatic nerve: case report and review of the literature. Surg Neurol Int. 2013;4:8.

    Article  Google Scholar 

  19. Markel SF, Enzinger FM. Neuromuscular hamartoma--a benign “triton tumor” composed of mature neural and striated muscle elements. Cancer. 1982;49:140–4.

    Article  CAS  Google Scholar 

Download references


Not applicable.


The study was supported by the National Research Foundation of Korea (award number: 2018M3A9E8078812). The role of the funding was in collection and interpretation of data and in writing the manuscript.

Author information

Authors and Affiliations



JHS coordinated the study, TSJ collected and interpreted data from the case and drafted the manuscript, IKP and HJK were involved with manuscript revision. All authors have read and approved the manuscript.

Corresponding author

Correspondence to Jae-Ho Shin.

Ethics declarations

Ethics approval and consent to participate

The study was approved by the Institutional Review Board of Kyung Hee University Hospital at Gangdong (KHU- 2019-11-017).

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 from the Editor-in-Chief of this journal.

Competing interests

The authors declare that they have no competing interests.

Additional information

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Joo, TS., Kim, H., Park, IK. et al. Incidental Hamartoma in an elderly patient: a case report. BMC Ophthalmol 20, 334 (2020).

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: