1992, The British Journal of Radiology, 65, 1040-1042
Case reports
Transitional cell carcinoma of the bladder associated with Crohn's disease: case report and review of the literature By *Y. Fujimura, MD, T. Kihara, MD, J. Uchida, MD, K. Hoshika, MD, * l . Sato, MD, tT. Eimoto, MD, Y. Furukawa, MD, tA. Sone, MD and §K. Ohashi, MD Divisions of *Gastroenterology and tNephrology, Department of Internal Medicine; and Departments of tUrology and §Family Practice, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-01, Japan
(Received 25 November 1991 and in revised form 12 March 1992, accepted 26 March 1992) Keywords: Transitional cell carcinoma, Bladder tumour, Crohn's disease, Adolescent
Transitional cell carcinoma of the bladder rarely occurs within the first two decades of life. We report a case of transitional cell cancer of the bladder complicating Crohn's disease and review the relevant literature. Case report The patient was a 15-year-old boy admitted to hospital in May 1990 with a fever and diarrhoea of four years' duration. There was no relevant past or family history. On admission, his temperature was 38.2°C and there was tenderness on palpation of the right lower quadrant. Laboratory findings on admission were as follows: white blood cell count was normal, C-reactive protein was 4.2 mg/dl (normal < 0.3 mg/dl), the erythrocyte sedimentation rate was 30 mm/h, albumin was 2.2 g/dl Address for correspondence: Yoshinori Fujimura, MD, Division of Gastroenterology, Department of Internal Medicine,- Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-01, Japan.
Figure 1. Ultrasonogram of the bladder, showing a papillary tumour.
1040
(normal, 3.5-4.5 g/dl), cholesterol was 92 mg/dl (normal, 130-220 mg/dl) and other blood tests were within normal limits. There were 20-25 red blood cells per high-power field in his urine. A chest radiograph was normal. A double-contrast examination of the upper gastrointestinal tract and a barium enema revealed typical Crohn's disease changes involving the ileum and proximal caecum, and a fistulous tract between the ileum and ascending and sigmoid colon. Treatment with total parenteral nutrition and elemental enteral hyperalimentation was commenced. Two months later, abdomen ultrasound with a full bladder showed an unexpected 1.5 cm papillary tumour localized in the lower right posterior wall of the bladder (Fig. 1). An excretofy urogram (Fig. 2) was performed and showed a filling defect. The tumour was resected at cystoscopy and shown to be a finger-like papillary tumour with a stalk (Fig. 3). The pathological finding was a Grade II transitional cell carcinoma
Figure 2. Excretory urography demonstrating a filling defect on the right lateral wall of the bladder (arrow). The British Journal of Radiology, November 1992
Case reports
Figure 3. Dissecting micrograph of a resected specimen using transurethral electrocoagulation. A stalk (arrow) is recognized at bottom of the specimen. without muscular invasion. The stalk was free of tumour. No recurrence was seen on ultrasound and cystoscopy 14 months later. Discussion
Javadpour and Mostofi (1969) reported that primary epithelial tumour of the bladder in the first two decades of life is rare. Transitional cell carcinoma of the bladder is uncommon in this age group and approximately 100 patients have been described in the literature (Mauermayer et al, 1977; MacCarthy et al, 1979; Benson et al, 1983). The majority of cases presented with macrohaematuria. Our patient had transient and asymptomatic microhaematuria recognized on urinalysis only at admission. Although the diagnosis of bladder tumours is confirmed at cystoscopy, their discovery may be delayed, as in our case, by transient and asymptomatic microhaematuria. Recently, ultrasound examination as a noninvasive method has been widely used in Japan. In this case, we found a papillary tumour of the bladder on ultrasound examination of the abdomen. Ultrasound may be useful as the initial screening test for patients with haematuria. Most reports (Mauermayer et al, 1977; MacCarthy et al, 1979; Benson et al, 1983; Lalmand et al, 1988) have indicated that epithelial bladder tumours in children and adolescents are morphologically and clinically benign with favorable prognoses because of both low rate of recurrence and low grade of malignancy. In general, it is considered that potentially carcinogenic predisposing conditions for bladder cancer in the young are cigarette smoking (Benson et al, 1983), schistosomiasis (Brumskine et al, 1977) and unusual exposure to paints, solvents, and chemicals (Benton & Henderson, 1973). However, we found no evidence of these conditions in this case. It is well known that Crohn's disease may involve the urinary tract and may appear as a mass in the bladder due to compression and invasion by an enlarging intraabdominal abscess. This was not true in this case. Radiographic features mimicking a primary bladder Vol. 65, No. 779
tumour have rarely been reported in Crohn's disease with ileovesical and rectovesical fistulas (Goldstein et al, 1971; Joffe, 1976; Edelman & Sternberg, 1980; Evans, 1990). It should be noted that the inflammatory changes in Crohn's disease closely resemble bladder tumours on radiography and cystoscopy. Recently, extraintestinal cancers associated with Crohn's disease have been reported. A review of the literature (Fielding et al, 1972; Gyde et al, 1980; Greenstein et al, 1985; Kvist et al, 1986; Madjlessi et al, 1986; Ball et al, 1988; Nakajima et al, 1990) showed reports of extraintestinal cancer complicating Crohn's disease in a total of 96 cases. Our case of transitional cell carcinoma of the bladder complicating Crohn's disease in an adolescent is rare. Although extraintestinal cancers occur at various sites in Crohn's disease, early reports (Gyde et al, 1980; Greenstein et al, 1980, 1981) failed to identify a statistically significant increase of any particular site of cancer in Crohn's disease patients. In 1985, Greenstein et al reported a significant increase in both genito-urinary tumours and reticuloendothelial neoplasms in Crohn's disease. Genito-urinary tumours, especially squamous cell carcinomas of the perianal region and vulva, are thought to be related to long-term chronic irritation and alteration of immune status due to medication with immunosuppressive drugs. Bladder cancer complicating Crohn's disease has been reported in only five cases, including ours, in this review of the literature. Acknowledgment We thank Miss H. Nakaishi for typing the manuscript. References BALL, C. S., WUJANTO, R., HABOUBI, N. Y. & SCHOFIELD, P. F.,
1988. Carcinoma in anal Crohn's disease; discussion paper. Journal of the Royal Society of Medicine, 81, 217-219 BENSON, R. C , JR., TOMEIZA, K. M. & KELALIS, P. P., 1983.
Transitional cell carcinoma of the bladder in children and adolescents. Journal of Urology, 130, 54-55. BENTON,
B. &
HENDERSON,
B.
E.,
1973.
Environmental
exposure and bladder cancer in young males. Journal of the Na'tional Cancer Institute, 51, 269-270. BRUMSKINE, W., DRAGAN, P. & SANVEE, L., 1977. Transitional
cell carcinoma and schistosomiasis in a 5-year-old boy. British Journal of Urology, 49, 540. EDELMAN, M. J. & STERNBERG, S. S., 1980. A pseudotumor of
the urinary bladder. Clinical Bulletin, 10, 35-37. EVANS, R. H., 1990. Crohn's disease mimicking primary bladder tumour. British Journal of Urology, 65, 299-300. FIELDING, J. F., PRIOR, P., WATERHOUSE, J. A. & COOKE, W. T.,
1972. Malignancy in Crohn's disease. Scandinavian Journal of Gastroenterology, 7, 3-7. GOLDSTEIN,
M.
J.,
BRAGG,
D.
&
SHERLOCK,
P.,
1971.
Granulomatous bowel disease presenting as a bladder tumour. American Journal of Digestive Disease, 16, 337-341. GREENSTEIN, A. J., SACHAR, D. B., SMITH, H., JANOWITZ, H. D.
& AUFSES, A. H., JR., 1980. Patterns of neoplasia in Crohn's disease and ulcerative colitis. Cancer, 46, 403-407. GREENSTEIN, A. J., SACHAR, D. B., SMITH, H., JANOWITZ, H. D.
& AUFSES, A. H., JR. 1981. A comparison of cancer risk in Crohn's disease and ulcerative colitis. Cancer, 48, 2742-2745.
1041
1992, The British Journal of Radiology, 65, 1042-1044 GREENSTEIN, A. J., GENNUSSO, R., SACHAR, D. B., HEIMANN, T., SMITH, H., JANOWITZ, H. D. & AUFSES, A. H., JR., 1985.
Extraintestinal cancers in inflammatory Cancer, 56, 2914-2921.
bowel disease.
GYDE, S. N., PRIOR, P., MACARTNEY, J. C , THOMPSON, H., WATERHOUSE, J. A. H. & ALLAN, R. N., 1980. Malignancy in
Crohn's disease. Gut, 21, 1024-1029. JAVADPOUR, N. & MOSTOFI, F. K., 1969. Primary epithelial
tumors of the bladder in the first two decades of life. Journal of Urology, 101, 706-710. JOFFE, N., 1976. Roentgenologic abnormalities of the urinary bladder secondary to Crohn's disease. American Journal of Roentgenology, 127, 297-302. KVIST, N . , JACOBSEN, O . , N0RGAARD, P., OCKELMANN, H . H . , KVIST, H. K., SCHOU, G. & JARNUM, S., 1986. Malignancy in
Case reports LALMAND, B., AVNI, E. F., SIMON, J., VERHEST, A., SCHULMAN,
C. C. & STRUYVEN, J., 1988. Transitional cell papillary carcinoma of the bladder in a child. Pediatric Radiology, 17, 77-79. MACCARTHY, J. P., GAVRELL, G. J. & LEBLANC, G. A., 1979.
Transitional cell carcinoma of the bladder in patients under thirty years of age. Urology, 13, 487. MADJLESSI, S. H. M., FARMER, R. G. & WEICK, J. K., 1986.
Inflammatory bowel disease and leukemia. Diseases and Sciences, 31, 1025-1031.
Digestive
MAUERMAYER, W., TAUBER, R. & STEUER, G., 1977. Epitheliale
Harnblasentumoren im Kindesalter und beim Jugendlichen. Urologe (A), 16, 286. NAKAJIMA,
H.,
MUNAKATA,
A.
&
YOSHIDA,
Y.,
1990.
Extraintestinal cancers in Crohn's disease. Digestion, 47, 1-7.
Crohn's disease. Scandinavian Journal of Gastroenterology, 21, 82-86.
The Swiss cheese brain By A. Jackson, PhD, MRCP, FRCR, M. J. Dobson, MB, ChB, MRCP and P. N. Cooper, MA, MRCP Department of Neuroradiology, Manchester Royal Infirmary, Oxford Rd, Manchester M13 9WL, UK {Received 15 November 1991 and accepted 12 March 1992) Keywords: Cysticercosis, Magnetic resonance imaging, Computed tomography
Case report A 37-year-old Indian man presented with a 6-month history of focal and grand mal convulsions. He had emigrated from India 2 years previously and was working as a chef in a local restaurant. There was no significant past medical history. Initial investigations included a computed tomogram (CT) of his brain (Fig. 1), which demonstrated a number of small enhancing parenchymal lesions with surrounding low-attenuation changes which were attributed to oedema. A magnetic resonance (MR) scan was performed and is illustrated (Figs 2-4). What are the radiological findings? What is the diagnosis and what other information would you seek to confirm this? The MR images demonstrate multiple, well-defined lesions throughout the brain, which show a predilection for grey matter. On short repetition time (TR) images the lesions appear as well-defined, low-signal foci (Fig. 2). On long TR images the lesions demonstrate a central nidus ranging from low to high signal and greatly varying degrees of associated oedema (Fig. 3). The lesions show a variable degree of ring enhancement following gadolinium (Fig. 4). Close examination demonstrates a small focus of irregularity in some of the cyst walls particularly on the post-contrast image (Fig. 4, arrows). These appearances are pathognomonic of neurocysticercosis (Bowen & Post, 1991). The findings of similar cysts within skeletal muscle (Fig. 5) or positive radioimmunoassay of serum or cerebrospinal fluid (CSF) may support the diagnosis. Although they are specific, immunological tests are insensitive (Rodriguez-Carbajal & Boleaga-Duran, 1982) and CT and magnetic resonance imaging (MRI) currently form the most sensitive and specific diagnostic indicator. Address correspondence to Dr A. Jackson. 1042
Discussion Neurocysticercosis is an infestation of the central nervous system by Taenia solium, the pork tapeworm. Faecal shedding of eggs by the definitive host, man, leads to ingestion of eggs by the intermediate host, usually pig or man. The primary larvae, oncospheres, hatch in the intestine and are distributed haematogenously to the brain and other tissues where they develop into secondary larvae, cysticerci (Marquez-Monter, 1971). Human morbidity results from dead larvae within the central nervous system leading to seizures intracranial hypertension, basal arachnoiditis, focal neurological deficits or dementia (Torrealba et al, 1984). The use of MRI allows the recognition of live cysts, which has been of great significance since the introduction of effective chemotherapy using praziquantel (Sotelo etal, 1984). The MRI appearances of the cysticerci vary with the stage of development and with the area of involvement, which may be parenchymal, meningeal or ventricular (Carbajal et al, 1977). Parenchymal cysts are found primarily in cerebral grey matter although histologically many cortical cysticerci lie within sulci from which they burrow into the cortex. When a viable larva is present within the cyst, MRI will demonstrate an homogeneous CSF-like intensity on both long and short TR images except for a mural nodule, slightly hyperintense to grey matter on the long TR images, which represents the scolex of the larvae (Suss et al, 1986; Bowen & Post, 1991). In these early stages there is usually no evidence of contrast enhanceThe British Journal of Radiology, November 1992
Case reports
Transitional cell carcinoma of the bladder associated with Crohn's disease: case report and review of the literature By *Y. Fujimura, MD, T. Kihara, MD, J. Uchida, MD, K. Hoshika, MD, * l . Sato, MD, tT. Eimoto, MD, Y. Furukawa, MD, tA. Sone, MD and §K. Ohashi, MD Divisions of *Gastroenterology and tNephrology, Department of Internal Medicine; and Departments of tUrology and §Family Practice, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-01, Japan
(Received 25 November 1991 and in revised form 12 March 1992, accepted 26 March 1992) Keywords: Transitional cell carcinoma, Bladder tumour, Crohn's disease, Adolescent
Transitional cell carcinoma of the bladder rarely occurs within the first two decades of life. We report a case of transitional cell cancer of the bladder complicating Crohn's disease and review the relevant literature. Case report The patient was a 15-year-old boy admitted to hospital in May 1990 with a fever and diarrhoea of four years' duration. There was no relevant past or family history. On admission, his temperature was 38.2°C and there was tenderness on palpation of the right lower quadrant. Laboratory findings on admission were as follows: white blood cell count was normal, C-reactive protein was 4.2 mg/dl (normal < 0.3 mg/dl), the erythrocyte sedimentation rate was 30 mm/h, albumin was 2.2 g/dl Address for correspondence: Yoshinori Fujimura, MD, Division of Gastroenterology, Department of Internal Medicine,- Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-01, Japan.
Figure 1. Ultrasonogram of the bladder, showing a papillary tumour.
1040
(normal, 3.5-4.5 g/dl), cholesterol was 92 mg/dl (normal, 130-220 mg/dl) and other blood tests were within normal limits. There were 20-25 red blood cells per high-power field in his urine. A chest radiograph was normal. A double-contrast examination of the upper gastrointestinal tract and a barium enema revealed typical Crohn's disease changes involving the ileum and proximal caecum, and a fistulous tract between the ileum and ascending and sigmoid colon. Treatment with total parenteral nutrition and elemental enteral hyperalimentation was commenced. Two months later, abdomen ultrasound with a full bladder showed an unexpected 1.5 cm papillary tumour localized in the lower right posterior wall of the bladder (Fig. 1). An excretofy urogram (Fig. 2) was performed and showed a filling defect. The tumour was resected at cystoscopy and shown to be a finger-like papillary tumour with a stalk (Fig. 3). The pathological finding was a Grade II transitional cell carcinoma
Figure 2. Excretory urography demonstrating a filling defect on the right lateral wall of the bladder (arrow). The British Journal of Radiology, November 1992
Case reports
Figure 3. Dissecting micrograph of a resected specimen using transurethral electrocoagulation. A stalk (arrow) is recognized at bottom of the specimen. without muscular invasion. The stalk was free of tumour. No recurrence was seen on ultrasound and cystoscopy 14 months later. Discussion
Javadpour and Mostofi (1969) reported that primary epithelial tumour of the bladder in the first two decades of life is rare. Transitional cell carcinoma of the bladder is uncommon in this age group and approximately 100 patients have been described in the literature (Mauermayer et al, 1977; MacCarthy et al, 1979; Benson et al, 1983). The majority of cases presented with macrohaematuria. Our patient had transient and asymptomatic microhaematuria recognized on urinalysis only at admission. Although the diagnosis of bladder tumours is confirmed at cystoscopy, their discovery may be delayed, as in our case, by transient and asymptomatic microhaematuria. Recently, ultrasound examination as a noninvasive method has been widely used in Japan. In this case, we found a papillary tumour of the bladder on ultrasound examination of the abdomen. Ultrasound may be useful as the initial screening test for patients with haematuria. Most reports (Mauermayer et al, 1977; MacCarthy et al, 1979; Benson et al, 1983; Lalmand et al, 1988) have indicated that epithelial bladder tumours in children and adolescents are morphologically and clinically benign with favorable prognoses because of both low rate of recurrence and low grade of malignancy. In general, it is considered that potentially carcinogenic predisposing conditions for bladder cancer in the young are cigarette smoking (Benson et al, 1983), schistosomiasis (Brumskine et al, 1977) and unusual exposure to paints, solvents, and chemicals (Benton & Henderson, 1973). However, we found no evidence of these conditions in this case. It is well known that Crohn's disease may involve the urinary tract and may appear as a mass in the bladder due to compression and invasion by an enlarging intraabdominal abscess. This was not true in this case. Radiographic features mimicking a primary bladder Vol. 65, No. 779
tumour have rarely been reported in Crohn's disease with ileovesical and rectovesical fistulas (Goldstein et al, 1971; Joffe, 1976; Edelman & Sternberg, 1980; Evans, 1990). It should be noted that the inflammatory changes in Crohn's disease closely resemble bladder tumours on radiography and cystoscopy. Recently, extraintestinal cancers associated with Crohn's disease have been reported. A review of the literature (Fielding et al, 1972; Gyde et al, 1980; Greenstein et al, 1985; Kvist et al, 1986; Madjlessi et al, 1986; Ball et al, 1988; Nakajima et al, 1990) showed reports of extraintestinal cancer complicating Crohn's disease in a total of 96 cases. Our case of transitional cell carcinoma of the bladder complicating Crohn's disease in an adolescent is rare. Although extraintestinal cancers occur at various sites in Crohn's disease, early reports (Gyde et al, 1980; Greenstein et al, 1980, 1981) failed to identify a statistically significant increase of any particular site of cancer in Crohn's disease patients. In 1985, Greenstein et al reported a significant increase in both genito-urinary tumours and reticuloendothelial neoplasms in Crohn's disease. Genito-urinary tumours, especially squamous cell carcinomas of the perianal region and vulva, are thought to be related to long-term chronic irritation and alteration of immune status due to medication with immunosuppressive drugs. Bladder cancer complicating Crohn's disease has been reported in only five cases, including ours, in this review of the literature. Acknowledgment We thank Miss H. Nakaishi for typing the manuscript. References BALL, C. S., WUJANTO, R., HABOUBI, N. Y. & SCHOFIELD, P. F.,
1988. Carcinoma in anal Crohn's disease; discussion paper. Journal of the Royal Society of Medicine, 81, 217-219 BENSON, R. C , JR., TOMEIZA, K. M. & KELALIS, P. P., 1983.
Transitional cell carcinoma of the bladder in children and adolescents. Journal of Urology, 130, 54-55. BENTON,
B. &
HENDERSON,
B.
E.,
1973.
Environmental
exposure and bladder cancer in young males. Journal of the Na'tional Cancer Institute, 51, 269-270. BRUMSKINE, W., DRAGAN, P. & SANVEE, L., 1977. Transitional
cell carcinoma and schistosomiasis in a 5-year-old boy. British Journal of Urology, 49, 540. EDELMAN, M. J. & STERNBERG, S. S., 1980. A pseudotumor of
the urinary bladder. Clinical Bulletin, 10, 35-37. EVANS, R. H., 1990. Crohn's disease mimicking primary bladder tumour. British Journal of Urology, 65, 299-300. FIELDING, J. F., PRIOR, P., WATERHOUSE, J. A. & COOKE, W. T.,
1972. Malignancy in Crohn's disease. Scandinavian Journal of Gastroenterology, 7, 3-7. GOLDSTEIN,
M.
J.,
BRAGG,
D.
&
SHERLOCK,
P.,
1971.
Granulomatous bowel disease presenting as a bladder tumour. American Journal of Digestive Disease, 16, 337-341. GREENSTEIN, A. J., SACHAR, D. B., SMITH, H., JANOWITZ, H. D.
& AUFSES, A. H., JR., 1980. Patterns of neoplasia in Crohn's disease and ulcerative colitis. Cancer, 46, 403-407. GREENSTEIN, A. J., SACHAR, D. B., SMITH, H., JANOWITZ, H. D.
& AUFSES, A. H., JR. 1981. A comparison of cancer risk in Crohn's disease and ulcerative colitis. Cancer, 48, 2742-2745.
1041
1992, The British Journal of Radiology, 65, 1042-1044 GREENSTEIN, A. J., GENNUSSO, R., SACHAR, D. B., HEIMANN, T., SMITH, H., JANOWITZ, H. D. & AUFSES, A. H., JR., 1985.
Extraintestinal cancers in inflammatory Cancer, 56, 2914-2921.
bowel disease.
GYDE, S. N., PRIOR, P., MACARTNEY, J. C , THOMPSON, H., WATERHOUSE, J. A. H. & ALLAN, R. N., 1980. Malignancy in
Crohn's disease. Gut, 21, 1024-1029. JAVADPOUR, N. & MOSTOFI, F. K., 1969. Primary epithelial
tumors of the bladder in the first two decades of life. Journal of Urology, 101, 706-710. JOFFE, N., 1976. Roentgenologic abnormalities of the urinary bladder secondary to Crohn's disease. American Journal of Roentgenology, 127, 297-302. KVIST, N . , JACOBSEN, O . , N0RGAARD, P., OCKELMANN, H . H . , KVIST, H. K., SCHOU, G. & JARNUM, S., 1986. Malignancy in
Case reports LALMAND, B., AVNI, E. F., SIMON, J., VERHEST, A., SCHULMAN,
C. C. & STRUYVEN, J., 1988. Transitional cell papillary carcinoma of the bladder in a child. Pediatric Radiology, 17, 77-79. MACCARTHY, J. P., GAVRELL, G. J. & LEBLANC, G. A., 1979.
Transitional cell carcinoma of the bladder in patients under thirty years of age. Urology, 13, 487. MADJLESSI, S. H. M., FARMER, R. G. & WEICK, J. K., 1986.
Inflammatory bowel disease and leukemia. Diseases and Sciences, 31, 1025-1031.
Digestive
MAUERMAYER, W., TAUBER, R. & STEUER, G., 1977. Epitheliale
Harnblasentumoren im Kindesalter und beim Jugendlichen. Urologe (A), 16, 286. NAKAJIMA,
H.,
MUNAKATA,
A.
&
YOSHIDA,
Y.,
1990.
Extraintestinal cancers in Crohn's disease. Digestion, 47, 1-7.
Crohn's disease. Scandinavian Journal of Gastroenterology, 21, 82-86.
The Swiss cheese brain By A. Jackson, PhD, MRCP, FRCR, M. J. Dobson, MB, ChB, MRCP and P. N. Cooper, MA, MRCP Department of Neuroradiology, Manchester Royal Infirmary, Oxford Rd, Manchester M13 9WL, UK {Received 15 November 1991 and accepted 12 March 1992) Keywords: Cysticercosis, Magnetic resonance imaging, Computed tomography
Case report A 37-year-old Indian man presented with a 6-month history of focal and grand mal convulsions. He had emigrated from India 2 years previously and was working as a chef in a local restaurant. There was no significant past medical history. Initial investigations included a computed tomogram (CT) of his brain (Fig. 1), which demonstrated a number of small enhancing parenchymal lesions with surrounding low-attenuation changes which were attributed to oedema. A magnetic resonance (MR) scan was performed and is illustrated (Figs 2-4). What are the radiological findings? What is the diagnosis and what other information would you seek to confirm this? The MR images demonstrate multiple, well-defined lesions throughout the brain, which show a predilection for grey matter. On short repetition time (TR) images the lesions appear as well-defined, low-signal foci (Fig. 2). On long TR images the lesions demonstrate a central nidus ranging from low to high signal and greatly varying degrees of associated oedema (Fig. 3). The lesions show a variable degree of ring enhancement following gadolinium (Fig. 4). Close examination demonstrates a small focus of irregularity in some of the cyst walls particularly on the post-contrast image (Fig. 4, arrows). These appearances are pathognomonic of neurocysticercosis (Bowen & Post, 1991). The findings of similar cysts within skeletal muscle (Fig. 5) or positive radioimmunoassay of serum or cerebrospinal fluid (CSF) may support the diagnosis. Although they are specific, immunological tests are insensitive (Rodriguez-Carbajal & Boleaga-Duran, 1982) and CT and magnetic resonance imaging (MRI) currently form the most sensitive and specific diagnostic indicator. Address correspondence to Dr A. Jackson. 1042
Discussion Neurocysticercosis is an infestation of the central nervous system by Taenia solium, the pork tapeworm. Faecal shedding of eggs by the definitive host, man, leads to ingestion of eggs by the intermediate host, usually pig or man. The primary larvae, oncospheres, hatch in the intestine and are distributed haematogenously to the brain and other tissues where they develop into secondary larvae, cysticerci (Marquez-Monter, 1971). Human morbidity results from dead larvae within the central nervous system leading to seizures intracranial hypertension, basal arachnoiditis, focal neurological deficits or dementia (Torrealba et al, 1984). The use of MRI allows the recognition of live cysts, which has been of great significance since the introduction of effective chemotherapy using praziquantel (Sotelo etal, 1984). The MRI appearances of the cysticerci vary with the stage of development and with the area of involvement, which may be parenchymal, meningeal or ventricular (Carbajal et al, 1977). Parenchymal cysts are found primarily in cerebral grey matter although histologically many cortical cysticerci lie within sulci from which they burrow into the cortex. When a viable larva is present within the cyst, MRI will demonstrate an homogeneous CSF-like intensity on both long and short TR images except for a mural nodule, slightly hyperintense to grey matter on the long TR images, which represents the scolex of the larvae (Suss et al, 1986; Bowen & Post, 1991). In these early stages there is usually no evidence of contrast enhanceThe British Journal of Radiology, November 1992
