Pediatr Blood Cancer 2009;53:669–671

BRIEF REPORTLocalised Peripheral Primitive Neuroectodermal Tumour (PNET) of the Conjunctiva

Andrew S. Moore, MBBS,1*,{ Peter G. Wilson, MBBS, FRACP,2{ Penny McKelvie, MBBS, FRCPA,3#

Jamie La Nauze, FRANZCO, MMedSci(ClinEpi),4,§ and Lawrence W. Hirst, MD, MPH, FRANZCO5,§

INTRODUCTION

The Ewing sarcoma family of tumours (ESFT) are a group of

aggressive, small blue round cell tumours including classic Ewing

sarcoma of bone, extra-skeletal Ewing sarcoma, peripheral neuro-

ectodermal tumours (PNET, also known as peripheral neuro-

epithelioma) and the small cell tumour of the thoracopulmonary

region (Askin tumour). Usually occurring during adolescence,

ESFT have a slight predominance in males and an unusual

predilection for Caucasians. The prognosis for ESFT varies

depending on the size, location and resectability of the primary

lesion, presence or absence of metastases, type of genetic

rearrangement and age [1,2].

The cytogenetic hallmark of ESFT is the reciprocal translocation

t(11;22)(q24;q12), with breakpoints at the EWSR1 region of

chromosome 22 and EWSR2 region of chromosome 11, resulting

in an EWS-FLI1 fusion transcript in 85% of ESFT [3,4]. In

approximately 10% of cases the EWS fusion partner is the ERG

gene on chromosome 21q22. The remaining cases (<1% each)

usually involve pairings of EWS-ETV1, EWS-E1AF or EWS-FEV

[1,2]. The detection of one of these fusion transcripts by RT-PCR or

a breakpoint at EWSR1 or EWSR2 by fluorescence in-situ

hybridisation (FISH) is diagnostic [1–4].

The most common sites for ESFT are the pelvis (26%), femur

(20%), tibia/fibula (18%), chest wall (16%), upper limbs (9%) and

spine (6%). Approximately 25% of patients have metastatic disease

at diagnosis, usually lung (10%) or bone/bone marrow (10%).

Primary skull lesions, including those arising from the orbit account

for only 2% of cases [1,2]. There are limited case reports in the

literature describing metastatic ocular involvement of ESFT, but no

cases of primary conjunctival involvement [5,6].

CASE REPORT

A 16-year-old Caucasian male presented with a 3-month history

of an asymptomatic enlarging conjunctival lesion. The patient was

otherwise well and had no significant past medical history. There

was a family history of optic atrophy in the patient’s father and

paternal grandfather, but no history of malignancy.

The lesion was located just medial to the insertion of the medial

rectus muscle, approximately 5 mm from the limbus and extending

5 mm nasally. Clinically, the differential diagnoses included a

benign naevus and melanoma. The lesion was completely excised

with the closest lateral margin measuring 0.15 mm. Histologically,

the biopsy showed conjunctiva with a multinodular tumour in the

stroma adjacent to a benign compound naevus. The tumour was

composed of lobules and focal sheets of medium to large atypical

epithelioid cells with high nuclear/cytoplasmic ratio, a number of

apoptotic figures, scattered foci of necrosis and a number of mitotic

figures. There was eccentric eosinophilic cytoplasm in some cells

and prominent nucleoli. There was no peripheral palisading, no

squamous nor definite sebaceous differentiation and no perineural

nor vascular invasion (Fig. 1).

Immunohistochemistry showed diffuse strong membranous stain-

ing with CD99, strong filamentous reactivity for vimentin, strong

reactivity for CD56, focal reactivity with a membranous pattern for

cytokeratin 20 and MNF116 (a cytokeratin marker), focal reactivity for

BCL-2 but negative staining for desmin and WT-1. There was also

focal dot-like reactivity with cytokeratin 20. Chromogranin and

synaptophysin were negative. Three melanoma markers (repeat S100,

melan A and HMB-45) were negative in the tumour but reactive in the

adjacent naevus. FISH with the Ewing break-apart probe (22q12

EWSR1) demonstrated a split signal at 22q12, confirming the diagnosis

of a primitive neuroectodermal tumour (Fig. 2). PCR analysis of the

remaining paraffin-embedded tissue was attempted retrospectively but

failed due to RNA degeneration.

The patient underwent wide re-excision 3 weeks after the

initial resection, with no histological evidence of residual tumour.

A 16-year-old male presented with a 3-month history of anasymptomatic, enlarging conjunctival lesion. An excisional biopsywas performed and histologic and immunohistochemical examina-tion showed characteristic features of a peripheral primitive neuro-ectodermal tumour (PNET) adjacent to a benign compound naevus.FISH analysis, demonstrating a split-signal at 22q12, confirmed the

diagnosis. Staging investigations were negative confirming theprimary nature of the lesion. The patient was treated withlocal wide re-excision and chemotherapy. He remains alive andwell 29 months after initial resection. Pediatr Blood Cancer 2009;53:669–671. � 2009 Wiley-Liss, Inc.

Key words: conjunctiva; Ewing/PNET; Ewing sarcoma; ocular tumours; rare tumours; soft tissue sarcoma

� 2009 Wiley-Liss, Inc.DOI 10.1002/pbc.22062Published online 2 June 2009 in Wiley InterScience(www.interscience.wiley.com)

——————1Section of Paediatric Oncology, The Institute of Cancer Research &

Royal Marsden Hospital, Sutton, Surrey, UK; 2Queensland Children’s

Cancer Centre, Royal Children’s Hospital, Brisbane, QLD, Australia;3St Vincent’s Pathology, St Vincent’s Hospital, Melbourne, VIC,

Australia; 4Ballina Eye Centre, Ballina, NSW, Australia; 5Queensland

Eye Institute, University of Queensland, Brisbane, QLD, Australia

{Clinical Research Fellow.

{Paediatric Oncologist.

§Ophthalmologist.

#Pathologist.

*Correspondence to: Andrew S. Moore, Section of Paediatric

Oncology, The Institute of Cancer Research & Royal Marsden

Hospital, 15 Cotswold Rd, Sutton, Surrey, SM2 5NG, UK.

E-mail: andrew.moore@icr.ac.uk

Received 2 February 2009; Accepted 20 March 2009

The conjunctival wound healed well and vision was preserved. Staging

investigations including MRI of the brain and orbits, CT scans of chest,

abdomen and pelvis, technetium bone scan and bone marrow biopsies,

showed no evidence of disease elsewhere. A number of skin lesions

were subsequently removed but all were benign.

The patient was treated with 14 cycles of chemotherapy given

approximately every 21 days according to the standard arm of the

Children’s Oncology Group AEWS0031 protocol: vincristine 2 mg/

m2 on day 1, doxorubicin 37.5 mg/m2 on days 1 and 2 (omitted in

cycles 11 and 13) and cyclophosphamide 1,200 mg/m2 on day 1;

alternating with ifosfamide 1,800 mg/m2 on days 1–5 and

etopophos 114 mg/m2 on days 1–5. Pegylated granulocyte colony

stimulating factor (G-CSF) was given after each cycle. Chemo-

therapy was well tolerated and only complicated by a central venous

line infection requiring line replacement following cycle 11.

In view of the location of the lesion and wide re-excision failing

to show any sign of residual disease, it was decided not to administer

local radiation therapy. Re-evaluation after cycle 14 with MRI of

brain and orbits and CT scan of chest, abdomen and pelvis showed

the patient to be in complete remission. The patient remains in

complete remission both clinically and radiologically 29 months

after the initial resection. His vision is normal.

DISCUSSION

Whilst the histogenesis of ESFT has traditionally been

considered neuroectodermal in origin, the ability of ESFT to

display epithelial and mesenchymal characteristics and arise in

tissues not related to the neural crest means that other histogenic

mechanisms are possible [7]. Conjunctival epithelium, the primary

site of PNET in our patient, is derived embryologically from surface

ectoderm rather than neuroectoderm [8]. Ocular components

derived from neuroectoderm include the neural retina, retinal

pigment epithelium, pigmented and nonpigmented ciliary epithe-

lium, pigmented iris epithelium, sphincter and dilator muscles of the

iris, optic nerve, axons and glia and vitreous [8].

Although our patient’s lesion arose in the conjunctiva, its natural

history may be somewhat similar to cutaneous ESFT. Chow et al. [9]

reviewed 14 cases of cutaneous and subcutaneous ESFT treated at

St. Jude Children’s Research Hospital, plus 23 similar cases

reported previously in the literature. Similar to our patient, all the

reported cases were Caucasians in the second decade of life (median

age 15–16 years) with localised disease, and brief duration of

symptoms with a lump or mass (median 2 months). Those in whom

complete surgical resection was achieved had excellent local control

without the need for radiation [9].

Therapy cannot be evidence-based in such rare situations and

one must return to general principles. Given the high propensity for

micrometastatic spread in ESFT, chemotherapy was deemed

necessary for our patient. Radiation therapy was also carefully

considered but withheld in view of the complete absence of tumour

at primary re-excision and potential toxicity, including the risk of

radiation-induced cataract.

This case highlights the need for early and appropriate referral of

patients with unexpected and unusual tumours for further opinion with

respect to both diagnosis and management. The cooperation of both

adult and paediatric specialists involved in this case ultimately lead to

the correct diagnosis and appropriate treatment being undertaken in

a timely manner, with an excellent outcome for the patient.

Pediatr Blood Cancer DOI 10.1002/pbc

Fig. 2. Fluorescent in-situ hybridisation with the Ewing break-apart probe (22q12 EWSR1) demonstrating a normal (A) and split signal at 22q12

(B, green arrows). [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

Fig. 1. High power magnification (400�) showing a highly cellular

small round blue cell tumour with little cytoplasm arranged in cords and

lobules. [Color figure can be viewed in the online issue, which is

available at www.interscience.wiley.com.]

670 Moore et al.

ACKNOWLEDGMENT

The histological and FISH images were kindly provided by

Dr John Lukin and Dr Kevin Whitehead from Sullivan Nicolaides

Pathology.

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Pediatr Blood Cancer DOI 10.1002/pbc

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