I.N. Soomro ( Department of Pathology, The Aga Khan University Hospital, Karachi. )
N.Kayani ( Department of Pathology, The Aga Khan University Hospital, Karachi. )
S. Pervez ( Department of Pathology, The Aga Khan University Hospital, Karachi. )
A.S. Hussainy ( Department of Pathology, The Aga Khan University Hospital, Karachi. )
R. Ahmed ( Department of Pathology, The Aga Khan University Hospital, Karachi. )
S. Muzaffar ( Department of Pathology, The Aga Khan University Hospital, Karachi. )
S.A. Aziz ( Department of Pathology, The Aga Khan University Hospital, Karachi. )
S.H. Hasan ( Department of Pathology, The Aga Khan University Hospital, Karachi. )
Histologic diagnosis ultimately determines the prognosis and treatment of lesions causing spinal cord compression. Modem imaging techniques have revolutionized the procedure of localizing lesions pre¬senting with signs and symptoms of spinal cord compression. As a result, these lesions are more accessible for fine needle aspiration and biopsy. A quick diagnosis is possible if cytologic preparation is made. Similarly, intraoperative frozen section facility not only provides rapid diagnosis, but also offers oppor tunity of appropriate management decision there and then. Histology in many cases needs help of special stains and immunocytochemistry. This study looks at the histologic spectrum of these lesions, gender distribution and age range in Pakistani population (JPMA 48:266, 1998).
Spinal cord is a delicate structure which is protected by extension of meningeal coverings and encasement of vertebral bones. Being continuation of the brain, it is liable to develop all the lesions one encounters in former structure, however, the distribution of these lesions is different. We investigated histologic spectrum of lesions causing sings and symptoms of compressive myelopathy.
Material and Method
This study was a retrospective analysis of biopsy specimen having signs and symptoms of comrpessive myelopathy. The study period ranged from September, 1992 -June 1997. Biopsy material was received and fixed in 10% formalin except in cases where frozen section or cytologic diagnosis was requested. Processing was routinely done and diagnosis was on hematoxylin eosin stained sections. This was supplemented by appropriate special stains. Immunocytochemistry using Avidin Biotin Complex method was used for classification of lymphomas, using various monoclonal antibodies such as leukocyte common antigen, PanB and PanT markers (L26, UCHL). Other antibodies such as glial fibrillary acid proteins (GFAP), vimentin, cytokeratins, EMA, S100 and neuro-filament were also used to supplement diagnosis where H&E preparation did not show classic histologic picture.
We reviewed 110 biopsy specimens from lesions of spinal cord and adjacent structures. Wherever the clinical histoiy of the patient was given, the commonest presentation was paraplegiaor paraparesis. This was followed by quadriplegia or quadri paresis. Backache was next in order. In many cases, clinicians mentioned the site of the lesion determined radiologically rather than signs or symptoms of lesion.
Commonest histologic diagnosis was chronic granulomatous inflammation, mostly with other features of tuberculosis such as caseation necrosis and/or multinucleated giant cells. Material was obtained by surgical exploration or by fine needle aspiration. There were 46 cases (M19, F=27). The age range in both genders was almost similar (M=10-66 with a median age of 32 years, F=l0-67 with a median age of 43 years). In three cases, only features of chronic non-specific inflammation were present.
Schwannoma, abenign nerve sheath tumour was seen in 19 cases (M=14 withamedian age of 37.5 years, F=05 witha median age of 49 years). The age range was 14-60 in males and 23-67 in females.
Seventeen cases belonged to lymphoproliferative disorder category, all being males. Ten of these had plasmacytonia/multiple myeloma, age range being 41 to 74 years, median age was 61 years. Other lymphomas included first ever case of T-ceIl rich B cell lymphoma presenting as spinal cord lesion in the world literature. There was also a single case of Hodgkin’s disease.
Meningiomas, all benign were seen in 10 patients. There was usual female predominance with 8 cases. The age range in females was 30-70 years with a median age of 39 years. The age in two males was 18 and 49 years. All meningiomas had psammoma bodies.
Chordoma, a tumour arising from remnants of notochord was seen in 3 cases, 2 males (44 and 65 years) and a female (28 years). Neurofibroma was diagnosed in 3 patients , [(M=01[58 year old )],[F=02 (F35 and 61 years old)]. Metastatic adenocarinoma was seen in 3 cases [(m=02)(57 and 59 years old)], [F=01(45 years old)]. Inone case, Primary site was kidney, in other 2, primary site remaind unknown.
Two cases of high grade astrocytoma were diagnosed in a male of 22 years and a female of 21 years. Among bone tumours, only 2 cases of giant cell tumour from vertebral bodies were diagnosed, one in a male and one in a female each 38 years old. Myxopapillay ependymoma was seen in a 49 year old male. A rare epidermoid cyst was diagnosed in a 23-year old male.
Unfortunately, tuberculosis remains the leading cause of morbidity related to spinal cord.This reflects the overall burden of the disease in the community. Although therc is rise in the incidence of tuberculosis in the developed world, this is due to growing population of immuno-compromised patients, particularly AIDS related. Situation is alarming in this country, where health of the nation is lowest priority in public sector. Health care delivery system, both the preventive and curative aspects need major overhauling and attention of authorities. Tuberculous osteomyelitis of vertebral bone is mostly hematogenous infection commonly seen in young adults, although this may follow tuberculous meningitis. This leads to destruction of cartilage, collapse and cord compression. Fever and other associations of tuberculosis were not presenting features in most cases - There was a female preponderance. One patient was positive for hepatitis B and C virus. Although surgery yields more tissue for histologic diagnosis, fine needle aspiration is equally affective for cytologic diagnosis and culture of organisms1.
Next common lesion was a benign nerve sheath tumour, Schwannoma. There was a male predominance. Almost all age groups were affected. These lesions are mostly intradurni extramedullary. lntramedullary lesions are rare. In practice, distinction between intrainedullary and extrarnedullary spinal Schwannonias is not always easy, since nerve root tumour invaginating the cord may become partially intmmedullaiy. Conversely, intrnmedullaiy lesions may traverse the Pia to become partially extramedullaiy2. Grossly, the lesions are usually well circumscribed and globular. The classic Schwannoma is a biphasic lesion exhibiting alternating areas of compact fascicular tissue (Antoni A pattern) and loose textured spongy tissue (Antom B pattern) histologically.
Surprisingly, all lymphoproliferative lesions were seen in males. A large fraction of lesions belonged to plasmacytoma/multiple myeloma group. During this five year period, 44 cases of plasmacytoma/multiple myelorna were diagnosed, only 13 were from biopsies of vertebral region. A definite diagnosis of multiple rnyeloma apart from biopsy, requires multiple osteolytic lesions and serum immunoelectrophoresis. Clinical information regarding these findings should always be communicated to the histopathologist along with the tissue.
Due to difference in the prognosis and treatment protocol, an effort should be made to classify lymphornas by iminunophenotyping and genotyping. We encountered a case of newly described lymphoma entity, T cell rich B-cell lymphoma with the help of Pan T and Pan B immunomarkers. Such a case presenting as an epidural mass has not yet been reported in the world literature. We also reported a case of Hodgkin’s disease. It remains unclear whether isolated lymphomas were truly primary in the epidural space or represent spread from occult prirnary elsewhere3.
There were 10 cases of intraspinal meningiomas, 8 in females, a well known female prepondrance. All these lesions had calcified structures called Psammoma bodies. Psammonatous meningiornas have predilection for spinal dura. Most have indolent biologic behavior. These tumours expand at the expense of the adjacent spinal cord to produce the expected segmental neurologic deficits. Most intraspinal meningiomas are intradural extramedullary lesions4. However, we have a rare case of epidural spinal meningioma in our series.
Chordoma. a destructive tumour which originates from remnants of notochord was seen in 3 patients. Lesion is infiltrative, osseodestructive and often lobulated5. The neoplastic cells are phenotypically mixed i.e., mesenchymal-epithelial shown by immunoreactivity for vimentin, cytokeratin and epithelial membrane antigen. Usually, the chordoma with its epithelial cords and distinctive physaliphorous cells lying in a mucoid matrix is diagnosed easily. But sometimes, distinction from chondrosarcoma is difficult and in these cases immunocytochemistry is resorted to. There was also a case ofmyxopapillary ependymomain our series. This variant of ependyrnoma is restricted to filum terminales. Histologically, lesion is characterized by pseudopapillary architecture, perivascular and inteitellular mucin deposition and tendency to cellular elongation.
Neurofibroma was seen in 3 patients. Association with neurofibromatosis was not known in these cases. Histologically, these lesions consist of schwann cells arrayed in short wavy bundles, separated by mucoid matrix. The differential diagnosis includes Schwannomas and meningiomas6. Intraspinal astrocytoma are rare lesions in contrast to intracranial tumour where it is the commonest primary malignancy. We reported 2 cases, both being high grade lesions. Grading is done principally on the basis of cellularity, mitotic activity, endothelial proliferation and necrosis7 . Four grades are assigned, grade III and IV are high grade lesions and pursue an aggressive clinical course.
There were three cases of metastatic adenocarcinoma, primary of one lesion was traced to kidney. Mostly they are solitary lesions which are aspirated or biopsied. Cord lesions are frequent in carcinomatosis, but due to difficult access to this site, other areas are explored to obtained diangostic material.
Among bone turnours, only 2 cases of giant cell tumour of vertebral bodies were diagnosed. This is amongst 88 giant cell tumours of bone diagnosed in five year period in the department. These tumours are locally osseodestructive lesions which impinge on adjacent structures8. These are formed by neoplastic, spindly cells with a uniform intermingled population of osteoclast giant cells. Anaplastic tumour with high mitotic rate can metastasize, but relatively benign looking lesions also posses this potential. Therefore, clinical behaviour of giant cell tumour is difficult to predict histologically.
There was a single case of epidermoid cyst in a 23 year old male. These occur throughout neuraxis, but most are intracranial. Rare intraspinal case report exists in world literature9. The uniloculate, thin walled epidermoid cyst has pearly quality due to content of Keratin. This is formed by well differentiated squamous epithelium, generating anucleate squames. Lesion is a benign entity.
On a number of occasions when the clinical and radiologic impression was of a spinal cord tumour, hisotlogic diagnosis revealed granulo ma tous inflammation and vice versa. Tissue diagnosis is therefore, imperative due to wide variety of lesions in this area with differing prognosis and treatment modalities. Radiologic localization, fine needle aspiration, frozen section and immunocytochernistry have complemented rapid and accurated diagnosis.
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