Managing prenatally diagnosed asymptomatic congenital cystic adenomatoid malformation.

Aim: To review our cases of congenital cystic adenomatoid malformation (CCAM) with special emphasis on the management of prenatally diagnosed asymptomatic CCAM (PDA-CCAM).

Methods: A total of 42 consecutive CCAM patients treated between 1990 and 2008 at our institution and affiliated hospitals were divided into four groups, according to whether prenatal diagnosis was made [PD (+) or (-)], whether patients were symptomatic [S (+) or (-)], whether there was any increase in size observed radiologically [R (+) or (-)], and whether surgical resection was performed [X (+) or (-)], to give a symptomatic early surgery group diagnosed prenatally (group A; n = 15): PD (+), S (+), R (+), X (+); an asymptomatic early surgery group diagnosed prenatally (group B; n = 8): PD (+), S (-), R (-), X (+); a conservative observation group diagnosed prenatally (group C; n = 6): PD (+), S (-), R (-), X (-); and a symptomatic surgery group diagnosed postnatally (group D; n = 13): PD (-), S (+), R (unknown), X (+). Patient demographics, effects of surgical stress, histopathology, and outcome were compared between the four groups.

Results: Groups A and B had surgery as neonates and mean duration of post-operative follow-up has been 15.7 months for group A and 63.3 months for group B. Group C has been under observation for a mean of 21.6 months (range: 10-40 months) with no incidence of infection. In group D, four had surgery as neonates after developing respiratory distress, and nine had surgery later (mean age: 4.1 years) after developing pneumonia (late onset group). Mean duration of follow-up for group D has been 48.0 months. In the late-onset group, pneumonia was successfully treated medically, and all nine had elective surgery with no intra- or post-operative complications. However, compared with group B (asymptomatic early surgery group diagnosed prenatally) the late-onset group had significantly longer duration of surgery (P < 0.05), significantly greater intraoperative blood loss (P < 0.01), and significantly higher peak post-operative C-reactive protein (P < 0.01), although there were no statistical differences for increase in white blood cell count ratios or length of hospitalization. Malignancy has not developed to date in any subject.

Conclusion: Our data suggest that patients with PDA-CCAM may be observed safely until they become symptomatic or changes in size are observed radiologically.