Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login 
Print this page Email this page Users Online: 388

 
LETTER TO THE EDITOR
Ahead of print publication  

Plexiform schwannoma masquerading as an appendageal tumor


1 Innovation Skin Clinic and Laser Center, Mumbai, Maharashtra, India
2 Department of Dermatology, Suasth Hospital, Kalamboli, Navi Mumbai, Maharashtra, India
3 Department of Dermatology, MGM Medical College and Hospital, Navi Mumbai, Maharashtra, India

Date of Submission27-Apr-2020
Date of Decision25-Jun-2020
Date of Acceptance07-Aug-2020

Correspondence Address:
Priyanka Patil,
A-6/702, Saraf Chaudhary Nagar, Thakur Complex, Kandivali (E), Mumbai - 400 101, Maharashtra
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/mjdrdypu.mjdrdypu_186_20



How to cite this URL:
Tambe S, Patil P, Jerajani H. Plexiform schwannoma masquerading as an appendageal tumor. Med J DY Patil Vidyapeeth [Epub ahead of print] [cited 2021 Feb 28]. Available from: https://www.mjdrdypv.org/preprintarticle.asp?id=309944



Dear Sir,

Schwannoma or neurilemmoma is true benign neoplasm of nerve sheath originating from Schwann cells. Schwannoma arises from nerve sheath of peripheral, cranial, or cutaneous nerves. Cutaneous schwannoma arise commonly from flexural aspect of extremities and head.[1] Plexiform schwannoma is a rare subtype constituting 5% of all the types of schwannoma. Macroscopically, it grows in a plexiform or multinodular pattern, mimicking plexiform neurofibroma.

A 28-year-old male patient presented with an asymptomatic small skin-colored lesion of 7 months' duration gradually increasing in size over the occipital area of the scalp. On examination, the lesion was a solitary, soft, 0.5 cm in diameter skin-colored papule. On palpation, deeper nodular component was felt [Figure 1]. The nodular deeper part was freely mobile and minimally tender on palpation with the normal hair over the surface.
Figure 1: Solitary, soft, 0.5 cm in diameter skin-colored papule on occipital area of scalp

Click here to view


Wide therapeutic wedge excision was done under local anesthesia [Figure 2]. The excised specimen showed a tumor mass in the dermis covered with thin fibrous capsule. Multi nodular well-defined encapsulated tumor masses of different sizes and shapes were seen in the dermal to subcutaneous tissue. The individual nodule composed of a hypercellular area (also called Antoni A type tissue) with proliferation of spindle cells, nuclei palisading around nodular to ribbon-like foci of fine fibrillary cell processes, Verocay bodies, and a hypocellular myxoid area (Antoni B type tissue) arranged in a nodular pattern confirming the diagnosis of plexiform schwannoma [Figure 3]a, [Figure 3]b, [Figure 3]c.
Figure 2: The excised specimen

Click here to view
Figure 3: (a) Multi nodular well-defined encapsuled tumor masses of different sizes and shapes in the dermal to subcutaneous tissue. (b) Multiple intradermal encapsulated nodules that vary in size and shape, and are separated from one another by loose or hyalinized fibrous stroma. (c) The individual nodule composed of a hypercellular area (also called Antoni A type tissue) with proliferation of spindle cells, nuclei palisading around nodular to ribbon-like foci of ?ne. A type t cell processes, Verocay bodies, and a hypocellular myxoid area (Antoni B type tissue) arranged in a nodular pattern

Click here to view


Diagnosis of the plexiform schwannoma was confirmed histologically, the patient was screened for acoustic schwannoma with magnetic resonance imaging (MRI) brain which did not reveal any abnormality. Final diagnosis of cutaneous plexiform schwannoma was considered.

Plexiform schwannomas (PS) are rare, benign, slowly growing, encapsulated tumors of Schwann cells arranged in plexiform pattern. Erlandson in 1985 classified Schwannomas into seven subtypes which is now widely used. It includes classical (Verocay), cranial nerve, cellular, plexiform (multinodular), ancient (degenerated), melanotic, and granular cell.[2] Macroscopically, PS grows in a plexiform or multinodular or worm-like pattern. It affects predominantly young adults with either sex and occurs mostly as a slowly growing, rarely painful, solitary, or multiple nodular lesions on the trunk, head and neck, or upper extremities. Classic schwannomas exhibit a positive Tinel's sign (pain on percussion of the lesion) if originated from the major peripheral nerves.

Histopathologically, the PS is made up of multiple intradermal encapsulated nodules that vary in size and shape, and are separated from one another by loose or hyalinized fibrous stroma characterized by two types of patterns: central hypercellular Antoni type A and peripheral myxoid Antoni type B. This zonation corresponds to the target sign. Furthermore, palisades of nuclei and Verocay bodies characterized by acellular processes that separate adjacent rows of palisaded nuclei are often observed and most of the tumor consists of Antoni type A tissue. It displays diffuse and strong S-100 protein staining.[3]

Immunohistochemical stains useful for the diagnosis of schwannoma are S100, epithelial membrane antigen, Leu-7, myelin basic protein, CD 34, CD 68, collagen types 1, 3, and 4, and vimentin.[4]

PS shows a specific multinodular pattern and hypointense capsule that separated the tumor from surrounding soft tissue on T2-weighted MRI.[5]

Plexiform schwannoma can be associated with neurofibromatosis type 2 but it is not associated with von Recklinghausen disease or a higher risk for malignant transformation.

The differential diagnosis of PS includes plexiform neurofibroma, plexiform fibrohistiocytic tumor, malignant peripheral nerve sheath tumors, palisaded encapsulated neuroma, and neurotropic melanoma. In general, surgical excision is the treatment of choice.

In conclusion, PS is rare and often misdiagnosed. It should be considered in the differentials of asymptomatic, round cystic swelling over scalp. Unique feature of our case is different clinical presentation of the tumor with papular superficial component mimicking an appendageal tumor and hidden deep nodular component.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Cho SB, Kim HS, Paik JH, Ryu DJ, Oh SH. Dome-shaped tumour with surface changes on the abdominal wall. Clin Exp Dermatol 2010;35:95-6.  Back to cited text no. 1
    
2.
Erlandson RA. Peripheral nerve sheath tumours. Ultrastruct Pathol 1985;9:113-22.  Back to cited text no. 2
    
3.
Kao GF, Laskin WB, Olsen TG. Solitary cutaneous plexiform neurilemmoma (schwannoma): A clinicopathologic, immunohistochemical, and ultrastructural study of 11 cases. Mod Pathol 1989;2:20-6.  Back to cited text no. 3
    
4.
Mohan Kh, Manjunath H. Cutaneous schwannoma masquerading as trichilemmal cyst over scalp in a young male. Indian J Dermatol 2013;58:407.  Back to cited text no. 4
[PUBMED]  [Full text]  
5.
Yamada K, Harada M, Kunitoku N, Goto S, Kochi M, Ushio Y. MR imaging features of a scalp plexiform schwannoma. AJNR Am J Neuroradiol 2004;25:291-4.  Back to cited text no. 5
    


    Figures

  [Figure 1], [Figure 2], [Figure 3]



 

 
Top
 
 
  Search
 
     Search Pubmed for
 
    -  Tambe S
    -  Patil P
    -  Jerajani H
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
   References
   Article Figures

 Article Access Statistics
    Viewed51    
    PDF Downloaded0    

Recommend this journal