1. CASE REPORT
Schwannoma and nerve abscess of leprosy:
differential diagnosis
CINTIA MARIA OLIVEIRA LIMA*,
PAULA CAPANEMA TEIXEIRA DA COSTA*,
LEONARDO CARNEIRO** & MARIA LEIDE W.
DE OLIVEIRA*
*Dermatology Service, Federal University of Rio de Janeiro
(HUCFF/UFRJ), Brazil
**Pathology Service, Federal University of Rio de Janeiro, Brazil
Accepted for publication 7 March 2013
Introduction
Schwannomas or neurilemomas are the most frequent nerve sheath tumours and could be
mistaken for a nerve abscess of leprosy as presented in this case report. These tumours may
affect any nerve in the body mainly in the flexor surfaces of limb and nerve trunks, often at
origin of spinal or cranial nerves.1
They usually grow slowly and appear as painless swellings
for several years before being diagnosed.
CASE REPORT
A 40 year-old man was treated in a basic health unit in the peripheral region of Rio de Janeiro
city with MB-MDT 12 months for borderline leprosy in 2006. He was referred to the
University Hospital to elucidate a suspicion of post-RFT nerve abscess in his left ulnar nerve.
He noticed a painful lump on palpation of the medial side of the left elbow and
intermittent paresthesia 1 year after leprosy treatment. He was started on treatment for Lepra
Reaction with prednisolone 40 mg /day and carbamazepine 200 mg/day for the paresthesias,
without clinical improvement. On examination there was an absence of skin lesions and a
painful nodular lesion of 5 cm on the medial side of the left elbow, without inflammatory
signs (Figure 1).
Absence of muscle wasting, weakness or claw and preserved skin sensation in the left
hand gave rise to doubts regarding leprosy etiology and a diagnosis of painful peripheral
nerve tumour was suggested. Ultrasound examination showed a hypoechoic nodule located in
Correspondence to: Maria Leide W. de Oliveira, Hospital Universita´rio Clementino Fraga Filho-Av.
Prof. Rodolpho Rocco, 255-Servic¸o de Dermatologia-58 andar-Ilha do Funda˜o-CEP:21.941.913 Brazil.
(e-mail: mleide@hucff.ufrj.br; mleide@uol.com.br)
Lepr Rev (2013) 84, 141–144
0305-7518/13/064053+04 $1.00 q Lepra 141

2. the medial insertion of the triceps above left epicondyle, of 2·38 x 0·95 cm mobile, with
heterogeneous texture which was removed. Histological examination of the tumour biopsy
(Hematoxylin–Eosin stained section) showed a benign schwannoma (Figure 2).
Discussion
When diagnosing Pure Neural Leprosy (PNL) based on nerve abscess caused by leprosy, the
differential diagnosis of Neurilemmomas derived from Schwann cells and neurofibroma
should be kept in mind, especially if there is no significant loss of function in the distribution of
the nerve. These constitute the two most common benign peripheral nerve sheath tumours.
Some atypical types of schwannoma have been described (ancient, psammomatous, melanotic,
cellular, benign epithelioid, neuroblastoma-like, plexiform).1
All ages are affected with a
peak between 30 to 60 years, and they have no predilection for race or sex. They arise within
the nerve sheath and are surrounded by a true capsule consisting of epineurium. The treatment
of choice is extracapsular or intracapsular removal under magnification.2
Histologically they
are described as Antoni type A (highly cellular, tightly compact spindle-shaped cells
which pallisade and produce Verocay bodies) and Antoni type B (less cellular and more
randomly arranged spindle cells in a loose, myxomatous stroma). In large or deep tumours
degenerative changes like cysts, calcification, hemorrhage and hyalinization are described.1
Recurrence is rare and has been seen in different areas of the nerves of the same
extremity, but not in operated sites. Because these tumours are slow-growing, soft in
Figure 1. palpation of a 5 cm painful nodular lesion on the medial side of the left elbow
C. M. O. Lima et al.142

3. consistency, mobile in nature, and sometimes painless, they are sometimes misdiagnosed as
lipoma, fibroma, ganglion, or xanthoma.2
The pure neuritic form of leprosy manifests as involvement of the nerve trunk and less
frequently as a painful lump – or nerve abscess. If it occurs in the absence of skin lesions it
could create a diagnostic problem. As seen in this case a soft tissue swelling in the ulnar nerve
without any obvious neurologic manifestation in the respective hand was mistaken for a nerve
abscess due to leprosy whereas it was actually a soft tissue tumour.3
Acid-fast bacilli (AFB)
in slit smears could be negative and the eletrophysiological exam is only suggestive, and is
not available in many endemic areas. The gold standard for PNL diagnosis is the
histopathological examination of a peripheral nerve, but bacteria are not always seen and
histological findings may be non-specific. Polymerase chain reaction (PCR) and detection of
antibodies against PGL-I in patients with peripheral neuropathy could also be useful but are
not available in the field,4,5
hence simple but careful sensory testing assessing heat, cold,
tactile and pinprick sensation is very useful in these cases. If these tests are doubtful, patients
should be referred for specialist opinion in order to avoid overdiagnosis/misdiagnosis of PNL.
Ultrasound examination is an inexpensive, non-invasive quick and repeatable technique
that can be used as an imaging modality for primary assessment of nerve tumour.1
The
utilization of Fine Needle Aspiration Cytology3
and Magnetic resonance imaging (MRI) can
be used to differentiate soft-tissue tumours. Despite being expensive, MRI is accurate in
locating the tumour, defining its origin, and showing the neurovascular structures.2
Leprosy reaction presenting as neuritis or nerve abscess occurs mainly during the first
months of treatment of leprosy, but can also occur before or even after treatment. Reactions
are the main cause of nerve damage and disability caused by leprosy.6
Though common in
Figure 2. Spindle cells associated with a highly vascularized stroma exhibiting Verocay bodies (HE 100X).
Schwannoma and nerve abscess of leprosy 143

4. these patients, we must be mindful of other differential diagnoses as in the case presented,
who were cured after being submitted for surgical excision.
The purpose of this report is to emphasize the complexity of PNL diagnosis in the field
and the importance of neurological assessment in the differential diagnosis of pure neural
leprosy, neuritis and neural tumours.
References
1
Traistaru R, Enachescu V, Manu D et al. Multiple right schwannoma. Rom J Morphol Embryol, 2008; 49:
235–239.
2
Ozdemir O, Kurt C, Coskunol E et al. Schwannomas of the hand and wrist: long-term results and review of the
literature. J Orthopaed Surg, 2005; 13: 267–272.
3
Siddaraju N, Sistla SC, Singh N et al. Pure Neuritic Leprosy With Nerve Abscess Presenting as a Cystic, Soft
Tissue Mass: Report of a Case Diagnosed by Fine Needle Aspiration Cytology. Diagn Cytopathol, 2009; 37:
355–358.
4
Jardim MR, Antunes SL, Simons B et al. Role of PGL-I antibody detection in the diagnosis of pure neural leprosy.
Lepr Rev, 2005; 76: 232–240.
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Bezerra Da Cunha FM, Werneck MC, Scola RH, Werneck LC. Pure neural leprosy: diagnostic value of the
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6
Souza LWF. Reac¸o˜es hanseˆnicas em pacientes em alta por cura pela poliquimioterapia. Rev Soc Bras Med Trop,
2010; 43: 737–739.
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