A subcutaneous manifestation of tuberous sclerosis complex in the posterior scalp

Abstract

Tuberous sclerosis complex (TSC) is an autosomal dominant syndrome due to a mutation in the TSC2 or TSC1 gene. The disease is known to have variable expressivity involving the neurological, cardiovascular, renal, pulmonary, and integumentary systems (Kennedy et al., 2017). We present a case report, and associated literature review, of a toddler with a posterior scalp lesion which was identified as a soft tissue fibroma upon histopathology. Unlike angiofibromas, soft tissue fibromas in the head and neck are not common in patients with TSC. This soft tissue tumor may be considered as one of the major criteria in the diagnosis of TSC.

Highlights

  • Soft tissue fibromas in the head and neck are uncommon in patients with Tuberous sclerosis complex (TSC).

  • A fibroma of the posterior scalp is not typical of TSC, and a literature search failed to return any reports of lesions in this area of the scalp.

  • To date, there is a lack of sufficient evidence to generate definitive management recommendations of these lesions.

Introduction

Tuberous sclerosis complex (TSC) is an autosomal dominant syndrome that manifests as cognitive impairment, seizures and hamartomas of the eyes, brain, kidneys, heart, lung and skin [ ]. Definitive diagnosis is defined as genetic criterion of mutation in the TSC 1 or TSC 2 gene. However, clinical criteria are still utilized in diagnosis due to the fact that genetic testing may not identify up to 25% of individuals with TSC, and normal gene testing may not exclude TSC [ ]. Patients may be considered to have TSC if they present with 2 major criteria or 1 major criterion and 2 minor features. Dental and head and neck specialists should be aware that the presence of three or more angiofibromas or one fibrous cephalic plaque are considered major features. Likewise, minor features include enamel pits and intraoral fibromas [ ].

Case report

A 2 year-old male with a known diagnosis of Tuberous Sclerosis Complex (TSC) presented with a subcutaneous lesion of the posterior scalp measuring approximately 6cm in length by 2cm in height ( Fig. 1 ). Per report, the lesion had been enlarging since birth and began as three separate nodules that had coalesced. Due to the patient’s aggressive and self-mutilating behavior, the lesion was constantly becoming traumatized and ulcerated with subsequent bleeding and increased infection risk. Upon examination, the lesion was firm and non-mobile. The overlying skin was largely devoid of hair. There were several areas of increased nodularity within the lesion. A CT of the head ( Fig. 2 ) as well as an MRI were obtained to assess for intracranial extension. After review of risks and benefits of surgical removal, the patient’s parents elected to proceed with surgical excision of the lesion.

Fig. 1
Soft tissue posterior scalp lesion.

Fig. 2
Pre-operative axial view of a CT Head depicting the subcutaneous lesion of the posterior scalp (soft tissue window).

The patient was taken to the operating room and general anesthesia was induced. The patient was positioned in a left lateral decubitus fashion and the proposed incision was marked. Local anesthesia was administered and sufficient time was allowed to elapse for maximum vasoconstrictor effect. The lesion was then removed using a combination of sharp dissection and electrocautery. The lesion was firmly adherent to the overlying dermis in several areas, but was easily dissected in a subgaleal plane. Interestingly, there was deformation of the occipital bone underlying the soft tissue lesion, but no violation of the calvarium. Following removal ( Fig. 3 ), the specimen was sent to surgical pathology for analysis. The excess skin was excised and the incision was closed in layers using 3-0 Vicryl suture to reapproximate the periosteum and galea in an interrupted fashion. The skin was closed using 3-0 chromic suture in a running interlocking fashion. A Glasscock dressing was placed over the wound to prevent the patient from causing direct trauma to the wound.

Aug 8, 2020 | Posted by in Oral and Maxillofacial Surgery | Comments Off on A subcutaneous manifestation of tuberous sclerosis complex in the posterior scalp
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