Indian Journal of Dermatology
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Year : 2014  |  Volume : 59  |  Issue : 5  |  Page : 530
Painful skin tumor over the back

Department of Dermatology, Government Stanley Medical College and Hospital, Chennai, Tamil Nadu, India

Date of Web Publication1-Sep-2014

Correspondence Address:
Rashmi Singh
Room No. 112, Ladies PG Hostel, Stanley Medical College, Chennai - 600 001, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0019-5154.139909

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How to cite this article:
Aravamuthan R, Rajendrabose RG, Singh R, Sudhakar S. Painful skin tumor over the back. Indian J Dermatol 2014;59:530

How to cite this URL:
Aravamuthan R, Rajendrabose RG, Singh R, Sudhakar S. Painful skin tumor over the back. Indian J Dermatol [serial online] 2014 [cited 2022 Dec 9];59:530. Available from:

A 27-year-old male presented with chief complaint of painful swelling present on lower back since early childhood, with increase in size and pain since past 3 years.

On dermatological examination, 4 × 3 cm, solitary, shiny, skin-colored, soft, lobulated and tender swelling on the right lower back [Figure 1]. The lesion was intradermal, vertically mobile and horizontally fixed. CT and MRI back revealed soft tissue swelling and no communication with internal structures.
Figure 1: Lobulated swelling over back

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Histopathological examination revealed a normal epidermis, and dermis showed encapsulated tumor consisting of spindle-shaped, wavy cells, with basophilic nuclei, arranged in bands with intervening eosinophilic cytoplasm [Figure 2] and [Figure 3]. Immunohistochemically, tumor cells stained positive for S100 proteins and negative for epithelial membrane antigen.
Figure 2: H and E (× 100, low power) Encapsulated tumor shows spindle-shaped cell in rows

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Figure 3: H and E (x400, high power) Spindle-shaped cells in rows with intervening eosinophilic areas

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   Question Top

What is your diagnosis?

   Answer Top

Diagnosis: Schwannoma

   Discussion Top

Schwannomas (neurilemmomas, anaxonal, Schwann cell tumors, peripheral neurogliomas) are benign, slow growing, encapsulated and expansile tumors of nerve sheaths composed of Schwann cells. Their peak incidence is fourth- fifth decade to seventh decade. They are common in head or flexor aspect of extremities [1] as solitary skin tumor along the course of peripheral or cranial nerves, especially VIII cranial nerve, associated with neurofibromatosis-2, as acoustic neuroma, or multiple cutaneous soft tissue or spinal schwannoma without acoustic neuroma or CNS tumors.

Their usual size is between 2 and 4 cm. Schwannomas are rare in the subcutaneous tissue; they are even less common in the dermis. Internal viscera and bones may be involved.

When small, most schwannomas are asymptomatic, but pain localized to tumor or radiating along the nerve of origin can be observed. Other painful skin tumors like Leiomyoma, Glomus tumor, Blue Rubber Bleb nevus, Eccrine poroma, Neuroma, Dermatofibrosarcoma, Tufted angioma, Angiolipoma, Eccrine spiradenoma, Granular cell tumor, Glomangioma, Myopericytoma, Malignant peripheral nerve sheath tumor (MPNST), which have their own clinical presentation and histological features to make differentiation. Immunohistochemistry is helpful in difficult cases. Malignant transformation is extremely rare and may contain areas of epitheloid angiosarcoma. [2]

Histopathologically, the tumor is rounded, circumscribed, and encapsulated. The cells are spindle-shaped, wavy, with basophilic nuclei, arranged in bands, which stream and interweave. The nuclei display palisading and are arranged in parallel rows with intervening eosinophilic cytoplasm in a typical appearance known as verocay bodies. Cellular areas, known as Antoni A areas, are intermixed with areas showing prominent myxoid change due to degeneration, known as Antoni B areas. [3] Variable amount of collagen are seen in the background. Scattered mononuclear inflammatory cells are often seen. S100 protein staining is strong and uniform [4] and negative for epithelial membrane antigen and smooth muscle markers which distinguish them from perineuroma and leiomyoma. A rare occurrence of hybrid lesions with features of neurofibroma and schwannoma may occur. [5] Immunostaining for neurofilaments present in neurofibroma differentiate both.

There are several variants of schwannoma, which may be confused histologically with other benign or malignant tumors, which include ancient, cellular, pacinian, plexiform, melanotic, neuroblastoma like, epitheloid, glandular schwannoma. [6] Carney syndrome consists of melanotic schwannoma, with myxoma, hyperpigmentation and endocrine over activity.

Once the diagnosis is established, simple excision is curative.

   References Top

1.Stout AP. The specific manifestations of peripheral nerve sheath tumors (neurilemmoma). Am J Cancer 1935;24:751-96.  Back to cited text no. 1
2.Woodruff JM, Selig AM, Crowley K, Allen PW. Schwannoma (neurilemmoma) with malignant transformation: A rare, distinctive peripheral nerve tumor. Am J Surg Pathol 1994;18:882-95.  Back to cited text no. 2
3.Sian CS, Ryan SF. The ultrastructure of neurilemoma with emphasis on Antoni B tissue. Hum Pathol 1981;12:145-60.  Back to cited text no. 3
4.Weiss SW, Langloss JM, Enzinger FM. Value of S-100 protein in the diagnosis of soft tissue tumors with particular reference to benign and malignant Schwann cell tumors. Lab Invest 1983;49:299-308.  Back to cited text no. 4
5.Feany MB, Anthony DC, Fletcher CD. Nerve sheath tumors with hybrid features of neurofibroma and schwannoma: A conceptual challenge. Histopathology 1998;32:405-10.  Back to cited text no. 5
6.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. 6
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