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Diprosopus (partially duplicated head) associated with anencephaly: a case report
PATHOLOGY RESEARCH AND PRACTICE
© Urban & Fischer Verlag
Diprosopus (Partially Duplicated Head) Associated with Anencephaly: A Case Report Abd AI Muti Zaitoun 1, John Chang 2 and Michael Booker3 ,Department of Pathology, 2Paediatrics and 30bstetrics & Gynaecology, Mayday University Hospital, London Road, Thornton Heath CR7 7YE, UK
Summary
Introduction
Craniofacial duplication (diprosopus) is a rare form of conjoined twin. A 16 year old mother with a twin pregnancy delivered one normally formed baby boy and one diprosopus male. The malformed baby was 33 weeks of gestation with a single trunk, normal limbs and various degrees of facial duplication. Of the following structures there were two of each: noses, eyes, ears (and one dimple), mouths, tongues and, with bilateral central cleft lips and cleft palates. This was associated with holoprosencephaly and craniorachischisis. Internal organs showed no duplication. There were multiple congenital anomalies including diaphragmatic hernia, small lungs, two lobes of the right lung, ventricular septal defect, small adrenal gland and small left kidney with short ureter. The body also had a short neck, small chest cavities and kyphosis. X-ray revealed duplication of the vertebral column. The case presented here represents a type II of diprosopia of Rating (1933) and is the least common type reported. We also reviewed 22 recently reported cases of diprosopus. In addition to facial duplication, anencephaly, neural tube defect and cardiac malformations represent the more common congenital abnormalities associated with diprosopus. The pathogenesis of diprosopus is not well understood. Factors that playa role in diprosopus are probably similar to those factors (genetic, environmental and abnormal placental circulation) which affect monozoygotic twins as observed in this case report. Early ultrasonography diagnosis of diprosopus permits one to consider a vaginal therapeutic abortion.
Conjoined twinning is a rare phenomenon that has been described in humans in many countries, races and time periods. The various forms of conjoining probably represent an aberration of the normal twinning process. Diprosopus (two faces) is a rare form of symmetric conjoined twins consisting of a single neck and body with various forms of duplication of craniofacial structure. Approximately 30 cases of diprosopus have been reported in the literature up to 1987 [10}. The rate of separation anomalies of monozygotic twins is assessed by a review of the literature; from 1120,000-1150,000 for joined twins and 11180,000-11 15,000,000 for disprosopia [13]. The etiology of diprosopus is unknown but it has been suggested that a slowing of oxidation affects the areas of the foetus undergoing the most rapid development and thereby causes a degree of twinning [19}. We report on a case of diprosopus associated with anencephaly. In addition to the neural tube defect, the baby had a congenital heart defect with other bone and internal abnormalities.
Key words: Anencephaly - Congenital malformation Craniofacial duplication - Diprosopus - Holoprosencephaly Pathol. Res. Pract. 195: 45-50 (1999)
Case report A 16 year old Caucasian healthy mother with twin pregnancy proceeded uneventfully up to the 33rd week. Sonographic examination revealed a twin pregnancy. One of the twins showed an anencephalic baby with Address for correspondence: A. M. Zaitoun, Dept. of Pathology, Mayday University Hospital, London Road, Thornton Heath, Surrey CR7 7YE, UK. Tel.: ++44 (181) 4013000 (ext: 4077), Fax: ++44 (181) 401-3189 0344-0338/99/195/1-045 $12.00/0
46 . A. A. Muti Zaitoun et al.
neural tube defect. This was confirmed by repeated scan and amniotic fluid was taken for a feto protein. Two male foetuses were delivered. One baby was externally normally formed but had a co-arctation of the aorta and the other was a disprosopus male. The malformed baby weighed 1,260 gms and the shoulder heel length was 30 cm. External examination
The baby was anencephalic, showing a single body, single head with facial duplication and normal well developed upper and lower limbs (Fig. 1). The faces were fused medially. There were two noses, two mouths, two tongues, two eyes, two ears and one dimple. The two adjacent cheeks were united and both chins and lower jaws were small (Fig. 2). These were associated with bilateral central cleft lips, cleft palates, anencephaly and craniorachischisis (measuring 13 cm in length). The clefting pattern of each face left a central premascillary
Fig. 1. Frontal view of the baby: an encephaly and incomplete facial duplication but normal appearance of the anterior aspect of the rest of the body.
Fig. 2. Incomplete facial duplication with central dimple and anencephaly.
Fig. 3. An anterioposterior radiograph demonstrating a duplicated vertebral column.
Diprosopus . 47
angle that is also characteristic of holoprosencephaly. Apart from cleft palate, the choanae were normal. The body showed short neck, small chest cavities and kyphosis. X-ray revealed duplication of the vertebral column throughout the spinal axis (Fig. 3) and x-ray of the head showed complex bone structure. Cytogenetic analysis of skin biopsy and testicular tissue revealed normal male karyotype 46XY. Internal examination
The base of the skull was covered by cerebrovascular and granulation tissue. No brain tissue was found. Examination of the spine revealed symmetrical duplication of the vertebral bodies. The spinal cord was completely lost at the site of cranioarchischisis with granulation and meningeal tissue found (Fig. 4). The lower part of the spinal cord showed meningeal tissue and the routes of the peripheral nerves. There were multiple congenital anomalies including diaphragmatic hernia with protru-
sion of part of the abdominal viscera into the chest cavity. This resulted in collapse of the left lung. The right lung showed two lobes. Both lungs were small as the result of the diaphragmatic hernia. The heart showed a small isolated ventricular septal defect in the upper part of the septum. In addition, there were two small adrenal glands and small left kidney (left kidney 6.4 gms, right kidney 8.2 gms) with short left ureter. The left kidney showed a small number of renal lobes in comparison with the right kidney. There was no evidence of renal dysplasia on histological examination. The placenta was monochorionic diarnniotic; total weight was 865 gms and trimmed weight 680 gms. The chorionic plate of the normal baby was slightly bigger than that of the diprosopus baby. Histological examination revealed mild congestion of the capillaries from both chorionic plates, which was more intense in the site of the normal baby. There was a small infarction (2 cm) with calcification. Some of the terminal chorionic villi were small with increased syncytial knots from the plate of the diprosopus twin. No oedematous changes were seen in the chorionic villi. The umbilical cords showed three blood vessels and the insertion of each was central and close to the dividing septum.
Discussion Diprosopus is a term applied to a fetus or baby having two faces but with close union of the head and body throughout. It is a rare teratism in man but more common in cattle, cats and pigs. Oldest representation of this anomaly in humans is the double headed twin god from Turkey 6,500 BC found in a Neolithic shrine as quoted by Turpin et al. [20]. The condition of diprosopia has been well described by Rating in 1933 [14J who classified disprosopia into three groups: Group I - duplication takes place in the upper half of the face. There are two eyes and a nose to each face with one common mouth. Group II - duplication takes place in the lower half of the face. There is a single face with two mouths. Group III - duplication is symmetrical and may be parallel. There is duplication of the nose and mouth but not of the eyes or ears.
Fig. 4. Severe craniorachischisis including the soft tissue with exposed meningeal and granulation tissue.
Our case belongs to the second group (Group II) and resembles the case reported by Soemmering in 1791 as quoted by Rating [14]. This form has two eyes and the dimple representing the two medial ears. Group II of Rating represents the least common forms of diprosopus reported in the literature. Review of 22 cases reported in the literature (Table 1) showed that anencephaly is reported in 67 percent of the cases [1,3,6,8,9,11,12,13,15,17]. Riccardi and Bergmann [15J categorised patients with anen-
4
1
3
37 weeks (2,600 g)
29 weeks (660 g)
20 weeks
12.
13.
14.
II.
3
4
3
27 weeks (1,785 g)
10.
2+2 primitive
4
3
35 weeks (2,630 g)
9.
2
4
3
31 weeks
16.
+
2+1
3
-
34 weeks (2,450 g)
Dextrocardia
Multiple
46XX
F
F
+
+
15.
F
+
2+1 primitive
3
3
28 weeks (1,210 g)
46XX
+
4
4
3
Multiple
F
Multiple
+
2+1 primitive
4
M
F
Cardiac anomalies
-meningomyelocoele
2
None
+
-
Multiple congenital anomalies
-
++
+
-
-
M
Multiple
-meningomyelocoele
46XX
Multiple
-neural tube defect
2+2 primitive
4
3
39 weeks (3,420 g)
8.
46XY
+
+
+
+
+
+
28
24
25
27
21
15
31
31
34
34
+
-
-
+
+
-
+
+
+
16
16
15
14
13
12
12
12
11
10
26 +
F
-
-
+
2
+
46XX
4
3
30 weeks
7.
2
5 +
-
8
7
6
References
M
Multiple
-
4
27 weeks (1,110 g)
6.
3
Multiple
+
2+1 primitive
4
31 weeks (850 g)
5.
Routine
Routine X-ray
-
Ultra Sonography X-ray
9
33
28
24
Age
-
-
-
Multiple
No post mortem
F
+
Nulli Multi parous parous
Mother
Small adrenals
+
2
4
46XX
F
Sex
+
5
30 weeks (850 g)
4.
3
Chromosomes
F
+
2
4
42 weeks (2,915 g)
3.
3
Not described
Internal organ abnormalities
+
+
35 weeks (2,273 g)
2.
-
aFP
F
2+1 primitive
4
3 +
Ears
Anencephaly
2+2 primitive
Eyes
Number of
3
30 weeks (1,000 g)
I.
Type of Disprosopia Rating 1933
Gestation & weight
Case No.
Table I.
~
~
::l
0l:::
e1.
l:::
=. N
~ ~ ~
QIC
...
Diprosopus . 49
'"Uo:l
..... ('l
00 0"..........
+
+
+
o
+
+ 00
(')
+
....
::l
+
.....
10
+ +
+
+
+
+
r-.....
.....
00
0\ .....
+
cephaly associated with monozygotic twinning into four groups: Group 1 - twins or triplets concordant for neural tube defect including anencephaly. Group 2 - twins discordant for neural tube defect. Group 3 - incomplete twins (diprosopus) with anencephaly. Group 4 - anencephaly or neural tube defect in the absence of twinning. This schema in tum emphasis that pathogenic factors relevant to the origin of monozygotic twinning may also be relevant to the origin of at least some instances of neural tube defect. Neural tube defect and rachischisis have been reported in association with diprosopus conjoined twinning [I, 3, 9, 11, 12}. Duplication of the spine was seen in our case and has been reported by other authors [8, 11, 16, 20}. Congenital anomalies in diprosopus are not confined to the head and vertebral column alone. In several cases, as in our case, there were cardiac anomalies [I, 2, 9, 10, 12,20,21]. In addition, our case showed multiple internal congenital anomalies and other authors have reported this association with diprosopus [I, 7, 9, 12, 13, 18, 20}. Some authors also reported an absence of the diaphragm [6, 12, 18}. The frequencies of diprosopus varies between 11180,000 to 1115,000,000 births [4, 13}. Conjoined twins are always of the same sex and show a single chorion and placenta. In diprosopus twins, the female to male ratio was 1.3/1 (Table 1). The findings suggest that they arise from a single ovum that has undergone abnormal fission. Although environmental stress early in embryonic development has been suggested as a possible factor for causing diprosopus, a twin birth of a morphologically normal male and one diprosopus, as in our case, suggests that factors other than the foetal environment may have contributed to the development of the diprosopus malformation. Since this pregnancy was monochorionic diamniotic this indicates that the surviving male is monozygotic to the disprosopus. The factors that playa role in diprosopus are probably similar to the factors in monozygotic twins. These include genetic, environmental and abnormal placental circulation. The changes in the placental vessels were minor and abnormal placental circulation cannot be excluded as a possible aetiological factor for the disprosoplus twin in this case. In experimental studies, lowering the temperature or reducing the oxygen concentration in the growth medium has produced anterior duplication in fish that is similar to disprosopus [l9}. The increase in neural tube defects in monozygotic twinning and of diprosopus support the possibility of embryonic migration or fusion [l8}. The prenatal diagnosis of diprosopus has recently been reported [3, 10, 13, 17}. In the majority of cases,
50 . A. A. Muti Zaitoun et al.
the diagnosis has been made late in the second trimester or third trimester (Table 1). The diagnosis of conjoined twins, prior to 24 weeks of gestation associated with anencephaly or other neural tube defects may permit termination of the pregnancy.
References 1. Arai T, Masaki S, Nikaido M (1962) A case of diprosopus. Acta Patho1ogica Japonica 12: 407-411 2. Barr M (1982) Facial Duplication: Case, Review and Embryogenesis. Teratology 25: 153-159 3. Carles D, Serville F, Horovitz J, Maugey B, Weichhold W (1989) Craniorachischisis chez des jumeaux conjoints Diprosopus. Ann Pathol9: 346-350 4. Castilla EE, Lopez-Camelo JS, Orio1i 1M, Sanchez 0, Paz JE (1988) The epidemiology of conjoined twins in Latin America. Acta Genet Med Gemellol 37: 111-118 5. Changaris DG, McGovern MH (1976) Craniofacial Publication (Diprosopus) in a twin. Arch Pathol Lab Med 100:392-395 6. Jaschevatzky OE, Goldman B, Kampf D, Wexler H, Grunstein S (1980) Etiological aspects of double monsters. Europ J Obstet Gynec reprod Bioi 10: 343-349 7. Kudo H, Toda S (1970) An Autopsy Case of Diprosopus. Acta Path Jap 20: 239-249 8. Maizels G (1938) Parallel Duplication of the Face in an Anencephalic Foetus. J Obstet Gynecol Br Emp 45: 679-774 9. Moerman PH, Fryns JP, Goddeeris P, Lauweryns 1M, Van Assche A (1983) Aberrant twinning (diprosopus) associated with anencephaly. Clinical Genetics 24: 252-256 10. Okazaki JR, Wilson JL, Holmes SM, Vandenmark LL (1987) DIprosopus: Diagnosis in Uteri. AJR 149: 147-148 11. Ornoy A, Navot D, Menashi M, Laufer N, Chemke J (1980) Asymmetry and Discordance for Congenital Anomalies in Conjoined Twins: A Report of Six Cases. Teratology 22: 145-154
12. Pavone L, Camera G, Grasso S, Gambini C, Barberis M, Garaffo S, Russo S (1987) Diprosopus with associated malformations: Report of two cases. Am J of Medical Genetics 28: 85-88 13. Picaud A, Nlome-Nze AR, Engongha-Beka T, Ogowet19umu N (1990) Diagnostic antenal prBcoce de jumeaux conjoints syncephaliques diprosopes. Rev Fr Gynecol Obstet 85: 379-381 . 14. Rating B (1933) Uber Eine Ungewohnliche GesichtsmBbildung bei Anencephalie. Virchow Arch Pathol Anat 288:223-242 15. Riccardi VM, Bergmann CA (1997) Anencephaly with Incomplete Twinning (Diprosopus). Teratology 16: 137-140 16. Richards DC, Easton PA (1941) Case of Diprosopus Tetranophthalmos. Am JObs & Gynecol41: 707-710 17. Rydnert J, Golmgren G, Nielsen K, Bergman F, Joelsson I (1985) Diagnosis of Conjoined twins (diprosopus) with myelomeningocele. Acta Obstet Gynaecol Scand 64: 687-688 18. Sharony R, Pepkowitz SH, Hixon H, Machin GA, Graham JM (1993) Diprosopus: A pregastrulation defect involving the Head, Neural Tube, Heart and Diaphragm Birth Defects. Original Article Series 29: 201-209 19. Stockard CR (1921) Development rate and structural expression. An experimental study of twins double monsters and single deforrnites, and the interaction among embryonic organs during their origin and development. Am J Anat 28: 115-263 20. Turpin 1M, Furnas DW, Amlie RN (1981) Craniofacial Duplication (Diprosopus). Plastic & Reconstructive Surgery 67: 139-142 21. Yu C-J, Lee W-D, Chi M-K, Lee Y-N, Lin Y-N (1988) Diprosopus - A case report. Chin Med J (Taipei) 41: 243-246
Received: February 6,1998 Accepted in revised form: October 5, 1998
© Urban & Fischer Verlag
Diprosopus (Partially Duplicated Head) Associated with Anencephaly: A Case Report Abd AI Muti Zaitoun 1, John Chang 2 and Michael Booker3 ,Department of Pathology, 2Paediatrics and 30bstetrics & Gynaecology, Mayday University Hospital, London Road, Thornton Heath CR7 7YE, UK
Summary
Introduction
Craniofacial duplication (diprosopus) is a rare form of conjoined twin. A 16 year old mother with a twin pregnancy delivered one normally formed baby boy and one diprosopus male. The malformed baby was 33 weeks of gestation with a single trunk, normal limbs and various degrees of facial duplication. Of the following structures there were two of each: noses, eyes, ears (and one dimple), mouths, tongues and, with bilateral central cleft lips and cleft palates. This was associated with holoprosencephaly and craniorachischisis. Internal organs showed no duplication. There were multiple congenital anomalies including diaphragmatic hernia, small lungs, two lobes of the right lung, ventricular septal defect, small adrenal gland and small left kidney with short ureter. The body also had a short neck, small chest cavities and kyphosis. X-ray revealed duplication of the vertebral column. The case presented here represents a type II of diprosopia of Rating (1933) and is the least common type reported. We also reviewed 22 recently reported cases of diprosopus. In addition to facial duplication, anencephaly, neural tube defect and cardiac malformations represent the more common congenital abnormalities associated with diprosopus. The pathogenesis of diprosopus is not well understood. Factors that playa role in diprosopus are probably similar to those factors (genetic, environmental and abnormal placental circulation) which affect monozoygotic twins as observed in this case report. Early ultrasonography diagnosis of diprosopus permits one to consider a vaginal therapeutic abortion.
Conjoined twinning is a rare phenomenon that has been described in humans in many countries, races and time periods. The various forms of conjoining probably represent an aberration of the normal twinning process. Diprosopus (two faces) is a rare form of symmetric conjoined twins consisting of a single neck and body with various forms of duplication of craniofacial structure. Approximately 30 cases of diprosopus have been reported in the literature up to 1987 [10}. The rate of separation anomalies of monozygotic twins is assessed by a review of the literature; from 1120,000-1150,000 for joined twins and 11180,000-11 15,000,000 for disprosopia [13]. The etiology of diprosopus is unknown but it has been suggested that a slowing of oxidation affects the areas of the foetus undergoing the most rapid development and thereby causes a degree of twinning [19}. We report on a case of diprosopus associated with anencephaly. In addition to the neural tube defect, the baby had a congenital heart defect with other bone and internal abnormalities.
Key words: Anencephaly - Congenital malformation Craniofacial duplication - Diprosopus - Holoprosencephaly Pathol. Res. Pract. 195: 45-50 (1999)
Case report A 16 year old Caucasian healthy mother with twin pregnancy proceeded uneventfully up to the 33rd week. Sonographic examination revealed a twin pregnancy. One of the twins showed an anencephalic baby with Address for correspondence: A. M. Zaitoun, Dept. of Pathology, Mayday University Hospital, London Road, Thornton Heath, Surrey CR7 7YE, UK. Tel.: ++44 (181) 4013000 (ext: 4077), Fax: ++44 (181) 401-3189 0344-0338/99/195/1-045 $12.00/0
46 . A. A. Muti Zaitoun et al.
neural tube defect. This was confirmed by repeated scan and amniotic fluid was taken for a feto protein. Two male foetuses were delivered. One baby was externally normally formed but had a co-arctation of the aorta and the other was a disprosopus male. The malformed baby weighed 1,260 gms and the shoulder heel length was 30 cm. External examination
The baby was anencephalic, showing a single body, single head with facial duplication and normal well developed upper and lower limbs (Fig. 1). The faces were fused medially. There were two noses, two mouths, two tongues, two eyes, two ears and one dimple. The two adjacent cheeks were united and both chins and lower jaws were small (Fig. 2). These were associated with bilateral central cleft lips, cleft palates, anencephaly and craniorachischisis (measuring 13 cm in length). The clefting pattern of each face left a central premascillary
Fig. 1. Frontal view of the baby: an encephaly and incomplete facial duplication but normal appearance of the anterior aspect of the rest of the body.
Fig. 2. Incomplete facial duplication with central dimple and anencephaly.
Fig. 3. An anterioposterior radiograph demonstrating a duplicated vertebral column.
Diprosopus . 47
angle that is also characteristic of holoprosencephaly. Apart from cleft palate, the choanae were normal. The body showed short neck, small chest cavities and kyphosis. X-ray revealed duplication of the vertebral column throughout the spinal axis (Fig. 3) and x-ray of the head showed complex bone structure. Cytogenetic analysis of skin biopsy and testicular tissue revealed normal male karyotype 46XY. Internal examination
The base of the skull was covered by cerebrovascular and granulation tissue. No brain tissue was found. Examination of the spine revealed symmetrical duplication of the vertebral bodies. The spinal cord was completely lost at the site of cranioarchischisis with granulation and meningeal tissue found (Fig. 4). The lower part of the spinal cord showed meningeal tissue and the routes of the peripheral nerves. There were multiple congenital anomalies including diaphragmatic hernia with protru-
sion of part of the abdominal viscera into the chest cavity. This resulted in collapse of the left lung. The right lung showed two lobes. Both lungs were small as the result of the diaphragmatic hernia. The heart showed a small isolated ventricular septal defect in the upper part of the septum. In addition, there were two small adrenal glands and small left kidney (left kidney 6.4 gms, right kidney 8.2 gms) with short left ureter. The left kidney showed a small number of renal lobes in comparison with the right kidney. There was no evidence of renal dysplasia on histological examination. The placenta was monochorionic diarnniotic; total weight was 865 gms and trimmed weight 680 gms. The chorionic plate of the normal baby was slightly bigger than that of the diprosopus baby. Histological examination revealed mild congestion of the capillaries from both chorionic plates, which was more intense in the site of the normal baby. There was a small infarction (2 cm) with calcification. Some of the terminal chorionic villi were small with increased syncytial knots from the plate of the diprosopus twin. No oedematous changes were seen in the chorionic villi. The umbilical cords showed three blood vessels and the insertion of each was central and close to the dividing septum.
Discussion Diprosopus is a term applied to a fetus or baby having two faces but with close union of the head and body throughout. It is a rare teratism in man but more common in cattle, cats and pigs. Oldest representation of this anomaly in humans is the double headed twin god from Turkey 6,500 BC found in a Neolithic shrine as quoted by Turpin et al. [20]. The condition of diprosopia has been well described by Rating in 1933 [14J who classified disprosopia into three groups: Group I - duplication takes place in the upper half of the face. There are two eyes and a nose to each face with one common mouth. Group II - duplication takes place in the lower half of the face. There is a single face with two mouths. Group III - duplication is symmetrical and may be parallel. There is duplication of the nose and mouth but not of the eyes or ears.
Fig. 4. Severe craniorachischisis including the soft tissue with exposed meningeal and granulation tissue.
Our case belongs to the second group (Group II) and resembles the case reported by Soemmering in 1791 as quoted by Rating [14]. This form has two eyes and the dimple representing the two medial ears. Group II of Rating represents the least common forms of diprosopus reported in the literature. Review of 22 cases reported in the literature (Table 1) showed that anencephaly is reported in 67 percent of the cases [1,3,6,8,9,11,12,13,15,17]. Riccardi and Bergmann [15J categorised patients with anen-
4
1
3
37 weeks (2,600 g)
29 weeks (660 g)
20 weeks
12.
13.
14.
II.
3
4
3
27 weeks (1,785 g)
10.
2+2 primitive
4
3
35 weeks (2,630 g)
9.
2
4
3
31 weeks
16.
+
2+1
3
-
34 weeks (2,450 g)
Dextrocardia
Multiple
46XX
F
F
+
+
15.
F
+
2+1 primitive
3
3
28 weeks (1,210 g)
46XX
+
4
4
3
Multiple
F
Multiple
+
2+1 primitive
4
M
F
Cardiac anomalies
-meningomyelocoele
2
None
+
-
Multiple congenital anomalies
-
++
+
-
-
M
Multiple
-meningomyelocoele
46XX
Multiple
-neural tube defect
2+2 primitive
4
3
39 weeks (3,420 g)
8.
46XY
+
+
+
+
+
+
28
24
25
27
21
15
31
31
34
34
+
-
-
+
+
-
+
+
+
16
16
15
14
13
12
12
12
11
10
26 +
F
-
-
+
2
+
46XX
4
3
30 weeks
7.
2
5 +
-
8
7
6
References
M
Multiple
-
4
27 weeks (1,110 g)
6.
3
Multiple
+
2+1 primitive
4
31 weeks (850 g)
5.
Routine
Routine X-ray
-
Ultra Sonography X-ray
9
33
28
24
Age
-
-
-
Multiple
No post mortem
F
+
Nulli Multi parous parous
Mother
Small adrenals
+
2
4
46XX
F
Sex
+
5
30 weeks (850 g)
4.
3
Chromosomes
F
+
2
4
42 weeks (2,915 g)
3.
3
Not described
Internal organ abnormalities
+
+
35 weeks (2,273 g)
2.
-
aFP
F
2+1 primitive
4
3 +
Ears
Anencephaly
2+2 primitive
Eyes
Number of
3
30 weeks (1,000 g)
I.
Type of Disprosopia Rating 1933
Gestation & weight
Case No.
Table I.
~
~
::l
0l:::
e1.
l:::
=. N
~ ~ ~
QIC
...
Diprosopus . 49
'"Uo:l
..... ('l
00 0"..........
+
+
+
o
+
+ 00
(')
+
....
::l
+
.....
10
+ +
+
+
+
+
r-.....
.....
00
0\ .....
+
cephaly associated with monozygotic twinning into four groups: Group 1 - twins or triplets concordant for neural tube defect including anencephaly. Group 2 - twins discordant for neural tube defect. Group 3 - incomplete twins (diprosopus) with anencephaly. Group 4 - anencephaly or neural tube defect in the absence of twinning. This schema in tum emphasis that pathogenic factors relevant to the origin of monozygotic twinning may also be relevant to the origin of at least some instances of neural tube defect. Neural tube defect and rachischisis have been reported in association with diprosopus conjoined twinning [I, 3, 9, 11, 12}. Duplication of the spine was seen in our case and has been reported by other authors [8, 11, 16, 20}. Congenital anomalies in diprosopus are not confined to the head and vertebral column alone. In several cases, as in our case, there were cardiac anomalies [I, 2, 9, 10, 12,20,21]. In addition, our case showed multiple internal congenital anomalies and other authors have reported this association with diprosopus [I, 7, 9, 12, 13, 18, 20}. Some authors also reported an absence of the diaphragm [6, 12, 18}. The frequencies of diprosopus varies between 11180,000 to 1115,000,000 births [4, 13}. Conjoined twins are always of the same sex and show a single chorion and placenta. In diprosopus twins, the female to male ratio was 1.3/1 (Table 1). The findings suggest that they arise from a single ovum that has undergone abnormal fission. Although environmental stress early in embryonic development has been suggested as a possible factor for causing diprosopus, a twin birth of a morphologically normal male and one diprosopus, as in our case, suggests that factors other than the foetal environment may have contributed to the development of the diprosopus malformation. Since this pregnancy was monochorionic diamniotic this indicates that the surviving male is monozygotic to the disprosopus. The factors that playa role in diprosopus are probably similar to the factors in monozygotic twins. These include genetic, environmental and abnormal placental circulation. The changes in the placental vessels were minor and abnormal placental circulation cannot be excluded as a possible aetiological factor for the disprosoplus twin in this case. In experimental studies, lowering the temperature or reducing the oxygen concentration in the growth medium has produced anterior duplication in fish that is similar to disprosopus [l9}. The increase in neural tube defects in monozygotic twinning and of diprosopus support the possibility of embryonic migration or fusion [l8}. The prenatal diagnosis of diprosopus has recently been reported [3, 10, 13, 17}. In the majority of cases,
50 . A. A. Muti Zaitoun et al.
the diagnosis has been made late in the second trimester or third trimester (Table 1). The diagnosis of conjoined twins, prior to 24 weeks of gestation associated with anencephaly or other neural tube defects may permit termination of the pregnancy.
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12. Pavone L, Camera G, Grasso S, Gambini C, Barberis M, Garaffo S, Russo S (1987) Diprosopus with associated malformations: Report of two cases. Am J of Medical Genetics 28: 85-88 13. Picaud A, Nlome-Nze AR, Engongha-Beka T, Ogowet19umu N (1990) Diagnostic antenal prBcoce de jumeaux conjoints syncephaliques diprosopes. Rev Fr Gynecol Obstet 85: 379-381 . 14. Rating B (1933) Uber Eine Ungewohnliche GesichtsmBbildung bei Anencephalie. Virchow Arch Pathol Anat 288:223-242 15. Riccardi VM, Bergmann CA (1997) Anencephaly with Incomplete Twinning (Diprosopus). Teratology 16: 137-140 16. Richards DC, Easton PA (1941) Case of Diprosopus Tetranophthalmos. Am JObs & Gynecol41: 707-710 17. Rydnert J, Golmgren G, Nielsen K, Bergman F, Joelsson I (1985) Diagnosis of Conjoined twins (diprosopus) with myelomeningocele. Acta Obstet Gynaecol Scand 64: 687-688 18. Sharony R, Pepkowitz SH, Hixon H, Machin GA, Graham JM (1993) Diprosopus: A pregastrulation defect involving the Head, Neural Tube, Heart and Diaphragm Birth Defects. Original Article Series 29: 201-209 19. Stockard CR (1921) Development rate and structural expression. An experimental study of twins double monsters and single deforrnites, and the interaction among embryonic organs during their origin and development. Am J Anat 28: 115-263 20. Turpin 1M, Furnas DW, Amlie RN (1981) Craniofacial Duplication (Diprosopus). Plastic & Reconstructive Surgery 67: 139-142 21. Yu C-J, Lee W-D, Chi M-K, Lee Y-N, Lin Y-N (1988) Diprosopus - A case report. Chin Med J (Taipei) 41: 243-246
Received: February 6,1998 Accepted in revised form: October 5, 1998