Multidimensional Ultrasound and Computed Tomography Imaging Support in Bleeding Plexiform Neurofibromatosis of the Scalp: A Case Report and Literature Review.

Active bleeding in plexiform neurofibromatosis can be a life-threatening complication in neurofibromatosis type 1 (NF1). The prompt imaging support of 2D-3D ultrasound (US) and computed tomography (CT) during the active hemorrhage phase of cutaneous neurofibromas has not been previously reported. We report a case with NF1 who experienced a sudden swelling in the parieto-temporal region that corresponded to a massive and active hemorrhage within a plexiform neurofibroma. The US and CT imaging characteristics of this bleeding tumor are shown. Active hemorrhage in a plexiform neurofibroma of the scalp appeared in US as a heterogeneous hypodermal mass. CT demonstrated a fully hyperdense soft tissue mass. These characteristics differ from the non-complicated or old hemorrhagic imaging appearances of scalp plexiform neurofibromas and encourage prompt surgical treatment. This case report demonstrates the usefulness of imaging support in the early diagnosis of this hemorrhagic complication of NF1 in the scalp and also stimulates multispecialty management.

What was known?

Neurofibromatosis type 1 may occasionally present hemorrhage as a life-threatening complication.

Two-dimensional imaging has shown the appearance of only uncomplicated and old hemorrhages in neurofibromas.

Introduction

Neurofibromatosis type 1 (NF1) is an autosomal dominant, multisystemic disorder caused by mutations of the gene NF1 that encodes the tumor suppressor protein neurofibromin.[1] Head and neck lesions may present as asymptomatic masses, pendulous and grotesque tumors, or space-occupying lesions producing pressure effects on the craniofacial bones and underlying structures. These tumors can show significant vascularization with abnormal vessel structure; however, spontaneous massive hemorrhage, a life-threatening complication, is rarely reported. Moreover, to date there are no reports in the literature about the 3D ultrasound features of hemorrhagic complications of NF in the scalp. Only a few reports on computed tomography (CT) of scalp findings in NF are available in the literature. As far as we know, none of the computed tomography reports have shown the tomographic features of the fully active phase of the bleeding in scalp NF which differs from the old hemorrhage.

Case Report

A 48-year-old male with a history of NF1 showing multiple “café-au-lait” spots and peripheral neurofibromas presented a sudden and tender swelling in the right parieto-temporal region of the scalp. The patient was referred to the Department of Radiology for a 2D-3D color Doppler ultrasound (CDUS) examination that demonstrated a hypodermal structure with lobulated margins and heterogeneous echogenicity, 8.3 cm long × 8.9 cm transverse × 1.6 cm depth axes. A 3.1 mm (thickness) serpiginous tubular mixed echogenicity (hypoechoic-anechoic) solid tract was also detected in the vicinity of the lesion. Neither intralesional blood flow nor involvement of the bony margin of the skull was detected on CDUS. A CT scan performed after the ultrasound examination demonstrated a fully hyperdense soft tissue mass in the same location of the scalp. The CDUS and the CT examinations were suggestive of bleeding plexiform NF. A surgical excision of the mass was performed and was consistent with the diagnosis. The histological analysis (hematoxylin and eosin stain) demonstrated a proliferation of spindle monomorphic cells embedded in the adipose tissue, some mastocytes, inflammatory cells, prominent capillary vessels and the presence of multiple hemorrhagic areas. Immunohistochemistry S-100 stained positive for spindle cells [Figures 1-4].

Figure 1

Clinical photograph of a 48-year-old male with history of NF1. The patient presented a sudden and tender swelling in the right parieto-temporal region

Figure 4

Histology (hematoxylin and eosin stain ×100 magnification) demonstrates a proliferation of spindle monomorphic cells (arrows) surrounding the adipose cells and the presence of a prominent hemorrhagic area (*)

2D and 3D Ultrasound (a) 2D panoramic grey scale transverse view; (b) 3D reconstruction longitudinal view; 5-8 seconds sweep) demonstrated a hypodermal structure with lobulated margins and heterogeneous echogenicity (8.9 cm transverse × 1.6 cm depth axes). Notice the anechoic areas (o) within the mass that corresponded to the most liquefied parts of the bleeding. There is a mixed echogenicity (anechoichypoechoic) serpiginous tract (arrow) in the vicinity of the structure. d: Dermis, h: Hypodermis, b: Bony margin of the skull

Computed tomography showing a hyperdense hemorrhagic soft tissue mass (*) in the right parieto-temporal region

Our local Ethics committee has waived the request of an informed consent for reporting this case, and the clinical, ultrasound and CT examinations were performed following the Helsinki principles of medical ethics.

Discussion

The clinical presentation of neurofibromas is variable and according to their morphology these entities can be classified into localized, diffuse and plexiform and they may show cutaneous, subcutaneous (hypodermal) or intraneural locations.[23] The characteristics and the degree of severity of NF1 are highly variable and its main clinical features include multiple “café-au-lait” spots, axillary freckling, hamartomas of the iris (Lisch nodules), optic pathway gliomas, peripheral nerve-sheath tumors and osseous involvement.[3]

The ultrasound imaging appearance of uncomplicated plexiform NF in the scalp has been previously described as a hypoechoic solid mass.[4] This appearance differs greatly in its imaging presentation from the complicated ultrasound features of the same tumor under hemorrhage, which shows a mixed echogenicity (heterogeneous) hypoechoic and anechoic solid-cystic structure. Even though the diagnosis can be performed with 2D ultrasound images, 3D images that require only a 5 to 8 seconds sweep show a more understandable representation of the pathology to the clinician. The serpiginous anechoic/hypoechoic tract that was observed in the periphery of the hematic fluid collection on ultrasound corresponds to a thick neural bundle, typically seen in plexiform NF.

Only a few cases have been described of the use of CT in giant plexiform neurofibromas affecting the scalp and cranio-maxillofacial regions.[56] These reports show old (non-active) areas of hemorrhage with heterogeneous density. This imaging presentation also differs from the fully active hemorrhage which is hyperdense in CT as in our case.

The presence of bleeding usually adds a more severe feature to the clinical condition that requires urgent treatment. Furthermore, hemorrhage in NF1, although rare, may be severe and recurrent and fatalities have been reported.[789]

The differential diagnosis of this case may include other soft tissue lesions of the scalp such as lipomas, trichilemmal cysts or pilomatrixomas where highly available imaging modalities such as ultrasound have been proven useful for assessing the diagnosis.[10]

In conclusion, we report this sudden hemorrhagic complication of a plexiform neurofibroma of the scalp that required urgent and coordinated work from the clinical, imaging and pathology staffs. This management was critical for the quick resolution of the case and shows the importance of prompt imaging support and the imaging characteristics of the bleeding in this entity both on multidimensional ultrasound and CT.

What is new?

Multidimensional imaging including 3D and 2D ultrasound as well as computed tomography can play a vital role in the assessment of the activity of the hemorrhagic complication of neurofibromatosis type 1. This is the first report of the simultaneous usage of 3D ultrasound and computed tomography in an actively bleeding neurofibroma of the scalp.