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Intraosseous Schwannoma of the Calcaneum
The Fool (1995) 5, 3840 0 1995 Pearson Professional Ltd
Intraosseous Schwannoma of the Calcaneum D. H. Sochart Orthopaedic Registrar, Bury General Hospital
S UMMA R Y. Intraosseous Schwannoma is a rare tumour accounting for only 0.2% of all primary bone tumours. It has never before been reported in the calcaneum and this case displays the typical history, presentation, radiological and histological lhulings. The tumour is benign and treatment is by excision of the tumour and curettage of the remaining cavity. If thorough, recurrence in rare and malignant transformation has never been reported.
CASE REPORT A 23-year-old lady presented with an 8-year history of intermittent discomfort and swelling of the lateral aspect of her right ankle. She was otherwise healthy with no past medical history of note and no history of trauma although she had presented to the Accident and Emergency Department on several occasions during the 8 years. On examination she was tender on palpation over the lateral aspect of her calcaneum but had a full range of pain free movements of her ankle and foot joints. There was no obvious swelling. X-rays (Figs 1 and 2) showed a cystic lesion of the calcaneum with sclerosis of the surrounding bone and attenuation of the lateral cortex. There was no calcification or lobulation within the lesion. Isotope bone scan (Fig. 3) demonstrated increased uptake in the lesion and CT scan (Fig. 4) confirmed the X-ray changes. It was felt that the radiological appearances confirmed a benign lesion and this was most likely to be due to Fig. 2-Axial
X-Ray
- right
calcaneum.
a aneurysmal bone cyst although it was felt that biopsy was required. At operation the lateral wall of the calcaneum was found to be very thin. A well encapsulated lesion was excised and the remaining cavity thoroughly curetted. Histological examination confirmed the diagnosis of Schwannoma with predominantly Antoni type A tissue and the presence of Verocay bodies.
.;,,+q&. .+ -..- % .s- q;;.
Fig. l-Lateral
X-Ray
”
---
lc ‘L.
,
- right
DISCUSSION
-e---z
-- : Z-F
Intraosseous Schwannoma is a rare benign neoplasm of neuroectodermal origin accounting for only 0.2%
calcaneum. 38
Intraosseous
Fig. J-Isotope
bone
scan - right
of the Calcaneum
39
usually solitary. The clinical onset is most common in the second and third decades and there is no predilection for sex.’ Delay in diagnosis is common and in one series the average duration of symptoms was 5.2 years3 Symptoms are mainly of discomfort and clinical findings consist of localised swelling and tenderness4 There is often a coincidental history of trauma leading to the discovery of the tum0ur.l Classically Schwannomas may arise centrally within the bone or within the nutrient canal itself and as they grow they perforate the cortex initially via the nutrient foramen. Frequently they project outside the bone and sometimes an extraosseous tumor may erode into the bone from the outside.5 The radiological findings are characteristic:
RI
ii
Schwannoma
leg.
1. A lytic lesion with sclerotic margins 2. Cortical erosion without periosteal new bone formation 3. Absence of central calcification or ossification within the lesion 4. Multiloculation and Trabeculation
Fig. 4-C.T.
scan - right
calcaneum
of all primary bone tumours, which are themselves relatively rare. Tumours of neural connective tissue were originally classified as ‘false neuromas’ by Virchow in 1858 and as ‘neurofibromas’ by Von Recklinghausen in 1882 but were more correctly classified by Shkler and Meyer in 1963, the Schwannoma being the least common tumour of neurogenic origin which tended to be solitary and slow growing. Only 80 cases have been reported in the world literature and none have involved the calcaneum. The most common sites of occurrence are the mandible and the sacrum (Table) and the only reported case in the foot involved the head of the fifth metatarsa1.l Intraosseous Schwannomas which are not associated with neuromafibromatosis are Table. Distribution schwannoma
of reported
cases of intraosseous
Site
Number
Mandible Sacrum Maxilla Ulna/femur Metacarpal, lumbar spine Cervical spine, thoracic spme. patella. fibula Temporal, scapula, rib, pubis.
22 21 5 4 3 2
humerus, tibia,
phalanges,
metatarsal
1
CT scan and MRI have helped in the detection and assessment of these tmnours but do not help with definitive diagnosis which still requires surgical biopsy.3 Histologically the appearances are identical to those in other soft tissue Schwannomas.6 The tumours are well circumscribed, encapsulated and usually solid although haemorrhage and necrosis may occur.7 There are areas of high cellularity called Antoni A tissue which may have pallisaded neuclei called Verocay bodies and less cellular areas of loose myxoid connective tissue (Antoni B tissue). Mitoses are either absent or rare but distended blood vessels with hyalinised walls and thrombi are common.7 There is often associated sclerosis of the surrounding bone. Treatment is by excision and curettage following which recurrence is rare and malignant transformation has not been reported.4 These tumours originate from sensory nerve fibres and the low density of these in bone probably accounts for the rarity of this tumour other than in the mandible or sacrum which contain sizeable sensory nerve branches. The case reported here is typical with regard to age at onset, delay in diagnosis, radiological and histological findings but intraosseus Schwannoma has not previously been reported in the calcaneum.
Acknowledgement I would like to thank Mr A. F. M. Brewood, Consultant Orthopaedic Surgeon at Bury General Hospital for permitting this report on his patient.
40 The Foot
References 1. Bailey S W, Williams J T, Baerg R W. Intraosseous Neurilemmoma of the Foot - A Case Report. Journal of the American Paediatric Association 1987; 77: 2944297. 2. Sanado L, Ruiz J L, Laider L. Femoral Intraosseous Neurilemmoma. Arch Orthop Trauma Surg 1991; 110: 212-213. 3. Adelwahab I F, Herman G. Case Report 564, Giant Intraosseous Schwannoma Skeletal. Radio1 1989; 18:
Skull - A Case Report. Neurochirurgia 1991; 34: 178-179. 6. Naidh M R, Dinaker I, Rao K S, Ratnaker K S. Intraosseous Schwannoma of the Cervical Spine. Clin Neurol Neurosurg 1988; 90: 257-260. 7. Turk P S, Peters N, Libbey P, Wanebo H. Diagnosis and Management of Giant Intrasacral Neuroma. Cancer 1992; 70: 2650-26.
The author
466-469.
De La Monte S M, Dorfmann H D. Intraosseous Schwannoma: Histological Features, Ultrastructure and Review of the Literature. Human Pathology 1984; 15: 551-558. 5. Schiffer J, Reif R. Intraosseous Neurilemmoma of 4.
D. H. Sochart,
FRCS
6 Saltire Gardens Tetlow Lane Manchester M7 OBG
Intraosseous Schwannoma of the Calcaneum D. H. Sochart Orthopaedic Registrar, Bury General Hospital
S UMMA R Y. Intraosseous Schwannoma is a rare tumour accounting for only 0.2% of all primary bone tumours. It has never before been reported in the calcaneum and this case displays the typical history, presentation, radiological and histological lhulings. The tumour is benign and treatment is by excision of the tumour and curettage of the remaining cavity. If thorough, recurrence in rare and malignant transformation has never been reported.
CASE REPORT A 23-year-old lady presented with an 8-year history of intermittent discomfort and swelling of the lateral aspect of her right ankle. She was otherwise healthy with no past medical history of note and no history of trauma although she had presented to the Accident and Emergency Department on several occasions during the 8 years. On examination she was tender on palpation over the lateral aspect of her calcaneum but had a full range of pain free movements of her ankle and foot joints. There was no obvious swelling. X-rays (Figs 1 and 2) showed a cystic lesion of the calcaneum with sclerosis of the surrounding bone and attenuation of the lateral cortex. There was no calcification or lobulation within the lesion. Isotope bone scan (Fig. 3) demonstrated increased uptake in the lesion and CT scan (Fig. 4) confirmed the X-ray changes. It was felt that the radiological appearances confirmed a benign lesion and this was most likely to be due to Fig. 2-Axial
X-Ray
- right
calcaneum.
a aneurysmal bone cyst although it was felt that biopsy was required. At operation the lateral wall of the calcaneum was found to be very thin. A well encapsulated lesion was excised and the remaining cavity thoroughly curetted. Histological examination confirmed the diagnosis of Schwannoma with predominantly Antoni type A tissue and the presence of Verocay bodies.
.;,,+q&. .+ -..- % .s- q;;.
Fig. l-Lateral
X-Ray
”
---
lc ‘L.
,
- right
DISCUSSION
-e---z
-- : Z-F
Intraosseous Schwannoma is a rare benign neoplasm of neuroectodermal origin accounting for only 0.2%
calcaneum. 38
Intraosseous
Fig. J-Isotope
bone
scan - right
of the Calcaneum
39
usually solitary. The clinical onset is most common in the second and third decades and there is no predilection for sex.’ Delay in diagnosis is common and in one series the average duration of symptoms was 5.2 years3 Symptoms are mainly of discomfort and clinical findings consist of localised swelling and tenderness4 There is often a coincidental history of trauma leading to the discovery of the tum0ur.l Classically Schwannomas may arise centrally within the bone or within the nutrient canal itself and as they grow they perforate the cortex initially via the nutrient foramen. Frequently they project outside the bone and sometimes an extraosseous tumor may erode into the bone from the outside.5 The radiological findings are characteristic:
RI
ii
Schwannoma
leg.
1. A lytic lesion with sclerotic margins 2. Cortical erosion without periosteal new bone formation 3. Absence of central calcification or ossification within the lesion 4. Multiloculation and Trabeculation
Fig. 4-C.T.
scan - right
calcaneum
of all primary bone tumours, which are themselves relatively rare. Tumours of neural connective tissue were originally classified as ‘false neuromas’ by Virchow in 1858 and as ‘neurofibromas’ by Von Recklinghausen in 1882 but were more correctly classified by Shkler and Meyer in 1963, the Schwannoma being the least common tumour of neurogenic origin which tended to be solitary and slow growing. Only 80 cases have been reported in the world literature and none have involved the calcaneum. The most common sites of occurrence are the mandible and the sacrum (Table) and the only reported case in the foot involved the head of the fifth metatarsa1.l Intraosseous Schwannomas which are not associated with neuromafibromatosis are Table. Distribution schwannoma
of reported
cases of intraosseous
Site
Number
Mandible Sacrum Maxilla Ulna/femur Metacarpal, lumbar spine Cervical spine, thoracic spme. patella. fibula Temporal, scapula, rib, pubis.
22 21 5 4 3 2
humerus, tibia,
phalanges,
metatarsal
1
CT scan and MRI have helped in the detection and assessment of these tmnours but do not help with definitive diagnosis which still requires surgical biopsy.3 Histologically the appearances are identical to those in other soft tissue Schwannomas.6 The tumours are well circumscribed, encapsulated and usually solid although haemorrhage and necrosis may occur.7 There are areas of high cellularity called Antoni A tissue which may have pallisaded neuclei called Verocay bodies and less cellular areas of loose myxoid connective tissue (Antoni B tissue). Mitoses are either absent or rare but distended blood vessels with hyalinised walls and thrombi are common.7 There is often associated sclerosis of the surrounding bone. Treatment is by excision and curettage following which recurrence is rare and malignant transformation has not been reported.4 These tumours originate from sensory nerve fibres and the low density of these in bone probably accounts for the rarity of this tumour other than in the mandible or sacrum which contain sizeable sensory nerve branches. The case reported here is typical with regard to age at onset, delay in diagnosis, radiological and histological findings but intraosseus Schwannoma has not previously been reported in the calcaneum.
Acknowledgement I would like to thank Mr A. F. M. Brewood, Consultant Orthopaedic Surgeon at Bury General Hospital for permitting this report on his patient.
40 The Foot
References 1. Bailey S W, Williams J T, Baerg R W. Intraosseous Neurilemmoma of the Foot - A Case Report. Journal of the American Paediatric Association 1987; 77: 2944297. 2. Sanado L, Ruiz J L, Laider L. Femoral Intraosseous Neurilemmoma. Arch Orthop Trauma Surg 1991; 110: 212-213. 3. Adelwahab I F, Herman G. Case Report 564, Giant Intraosseous Schwannoma Skeletal. Radio1 1989; 18:
Skull - A Case Report. Neurochirurgia 1991; 34: 178-179. 6. Naidh M R, Dinaker I, Rao K S, Ratnaker K S. Intraosseous Schwannoma of the Cervical Spine. Clin Neurol Neurosurg 1988; 90: 257-260. 7. Turk P S, Peters N, Libbey P, Wanebo H. Diagnosis and Management of Giant Intrasacral Neuroma. Cancer 1992; 70: 2650-26.
The author
466-469.
De La Monte S M, Dorfmann H D. Intraosseous Schwannoma: Histological Features, Ultrastructure and Review of the Literature. Human Pathology 1984; 15: 551-558. 5. Schiffer J, Reif R. Intraosseous Neurilemmoma of 4.
D. H. Sochart,
FRCS
6 Saltire Gardens Tetlow Lane Manchester M7 OBG