Talk:Placenta

Infarcts

Gross description

The specimen consists of a singleton placenta, received fresh in a container with patient identifiers.

Umbilical Cord:

• No. of segments: one, attached to the placental disc.
• insertion: marginal, not velamentous.
• length (aggregate): 19 cm.
• diameter: 1.8 cm (maximum).
• No. of vessels: three.
• coiling index (No. of coils/10 cm segment): 1
• comments: none.

Membranes:

• rupture site: distant from the cord and distant from the edge of the placental disc.
• colour: light green discolourization.
• comments: none.

Trimmed Placenta:

• size: 20 x 16.5 x 2 cm
• weight: 376 g (post-fixation).
• shape: irregular - described in 'maternal surface' section.
• comments: note.

Fetal Surface:

• colour: light green discolourization.
• vascularization: four vessels, unremarkable.
• comments: none.

Maternal Surface: completeness: cotyledons are complete. comments: two sites of thinning of the placental disc, with white dicolourization on the maternal aspect: site #1. 15 x 4 cm adjacent to the site of the cord insertion, site #2. 12 x 3 cm at the edge of the disc. There is no central depression and no significant blood clot present.

Parenchyma: comments: There are multiple large white, firm lesions and several smaller softer red lesions. The largest lesions measure 5, 4, 2.5, 2 cm. There is also a large recent thrombus in the central part of the disc measuring up to 2 cm. The percent of disc involved by the white and red lesions is estimated to be 20-25%.

Sections Submitted:

• 34: proximal cord and membranes
• 35: fetal and maternal surfaces, distal cord
• 36-38: full thickness (disc) - grossly unremarkable
• 39-40: red lesions (recent infarct)
• 41-42: white lesions (older infarcts)
• 43: white lesion in thinned region of disc (site #1) / interface of thinned region and central portion of the disc
• 44-45: white lesions (old infarcts)
• 46: white lesion in thinned region of disc (site #2)
• 47-49: additional sections of the membranes

Microscopic description

The sections show extensive placental infaraction, characterized by decreased intervillous spacing and karyolysis. There is extensive perivillous fibrin deposition and a large laminated intervillous thrombus.

A lymphocytic villitis with rare plasma cells is identified in less than five villi. The etiology of the lymphocytic villitis is not apparent by ordinary light microscopy examination and immunostaining for CMV. Placental mass is within the normal range for the estimated gestational age, 376 g (for 37 weeks 5 days, 10th percentile mass = 359 g, 50th percentile mass 468 g, 90th percentile mass = 610 g). If the mass of the placenta is assumed to be between the 10th and 90th percentile, it suggests a gestational age between 29 weeks 5 days and 38 weeks and 5 days.

Final diagnosis

Placenta, delivery - third trimester singleton placenta, with:

1. multiple placental infarcts, large (together 20-25% of placental volume), old and recent, see comment #1.
2. marked perivillous fibrin deposition within and around placental infarcts.
3. large intervillus thrombus (~2 cm).
4. lymphocytic villitis, very focal, see comment #2.
5. marginal cord insertion.

Comments

Comment #1 The extent of infarction is sufficient to exhaust the physiologic reserve and compromise placental function.

Comment #2 The extent of the villitis suggests this finding is probably inconsequential; however, it should be noted that severe lymphohistiocytic villitis is associated with adverse pregnancy outcomes, in a subset of patients.