What is the management approach for a placenta with an area lacking villous tissue, giving a perforated appearance?

Placenta with Perforated Appearance: Placenta Accreta Spectrum Disorder

A placenta with an area lacking villous tissue and a perforated appearance most likely represents placenta accreta spectrum (PAS) disorder, specifically an area of cesarean scar dehiscence with deep placental invasion, requiring immediate multidisciplinary surgical planning at a tertiary care center with hysterectomy capability. 1

Understanding the Pathologic Finding

The "perforated" or absent villous tissue appearance represents one of two critical pathologic patterns in PAS:

• Cesarean scar dehiscence pattern: The uterine wall is thinned to a few millimeters and composed entirely of fibrotic scar tissue, creating areas where normal placental architecture appears disrupted or "perforated" 1, 2

• Deep infiltrative invasion: Placental tissue directly invades through myometrium, creating an abrupt transition from normal myometrial thickness to placental parenchyma, which can appear as tissue defects on gross examination 1

• The area of dehiscence often comprises a large central portion of placental adherence, with infiltrative invasion typically found in sections adjacent to the scar 1

Critical Diagnostic Approach

Immediate ultrasound assessment is mandatory to evaluate for PAS-associated features:

• Loss of retroplacental clear zone (present in all PAS cases) 1, 3

• Myometrial thinning <1mm in the anterior uterine wall 3, 4

• Placental lacunae with turbulent lacunar blood flow on Doppler (distinguishes from benign placental lakes) 3, 5

• Hypervascularity of the uterovesical/subplacental area with bridging vessels and lacunae feeder vessels 4

• Massively dilated uterine vessels at the uteroplacental interface 1, 3

Grading and Surgical Planning

The pathologic grading system determines surgical approach 1:

• PAS Grade 3A (deep invasion): Irregular placenta-myometrial interface with <25% myometrial wall thickness preserved, intact serosa 1

• PAS Grade 3D (serosal disruption): Deep invasion with disruption of uterine serosal surface 1

• PAS Grade 3E (extrauterine invasion): Placental invasion into bladder or other pelvic organs 1

Management Algorithm

Immediate referral to level III/IV maternal care facility with the following capabilities 3:

1. Multidisciplinary team including maternal-fetal medicine, gynecologic oncology, interventional radiology, anesthesiology, and blood bank 6, 7

2. Planned cesarean hysterectomy at 34-37 weeks gestation (before labor or bleeding) 8, 6, 7

3. Interventional radiology support with internal iliac artery balloon occlusion catheters placed preoperatively to minimize hemorrhage 6, 7

4. Massive transfusion protocol availability, as blood loss with coagulopathy is expected 8, 6

Critical Pitfalls to Avoid

• Do not attempt manual placental removal if PAS is suspected—this causes catastrophic hemorrhage 8, 5

• Do not rely solely on ultrasound loss of clear zone for diagnosis, as this finding occurs in 100% of cases including non-PAS cesarean scar remodeling 4

• Do not diagnose based on scar dehiscence area alone—sections must include adjacent myometrium showing diagnostic PAS features 1

• Recognize amniotic fluid embolism risk: Abnormal placental architecture in PAS increases embolic phenomena risk during delivery 6

• Avoid delayed diagnosis: Uterine rupture can occur as early as 15 weeks gestation in severe PAS cases with prior cesarean sections 8

Pathologic Confirmation Requirements

Histologic examination must demonstrate 1:

• Loss of decidual layer at the uteroplacental interface (defining histologic feature) 1

• Villous tissue in direct contact with myometrium or surrounded only by fibrin and extravillous trophoblast (EVT) 1

• Deep EVT infiltration extending beyond decidua and inner myometrium into outer myometrial vessels 1

• Myometrial tissue injury with degenerated myofibers, interstitial edema, and chronic inflammation 1

The correlation between surgical findings, imaging, and pathology is essential for accurate diagnosis, as structural abnormalities from cesarean scar remodeling can mimic PAS on imaging without true villous invasion 4.