High Yield Info. No fluff. Here's some of the key features to know (for the boards)...
GENERAL INFO
THE BASICS:
Benign tumor, Curable by resection
TYPICAL CLINICAL PICTURE:
SPORADIC TYPE (most common):
OLDER female (50 yo) presents with a SINGLE mass in her LEFT ATRIUM near the fossa ovalis, appears MOBILE . Can cause symptoms similar to mitral valve stenosis
FAMILIAL (CARNEY COMPLEX) TYPE:
YOUNGER female (avg 26 yo) with MULTIPLE cardiac masses, can involve the RIGHT ATRIUM ; tend to recur more often than in sporadic myxomas.
HIGH YIELD ASSOCIATIONS:
CARNEY COMPLEX (7% of cases)= Autosomal Dominant
Myxomas (atrial & cutaneous)
Abnormal skin pigmentation
Endocrine OVERactivity (adrenal, pituitary, thyroid)
NAME
Nevi, Atrial Myxoma, Ephelides
LAMB
Lentigenes, Atrial Myxoma, Blue nevi
BUZZ WORD(S):
Mobile mass in (left) atria with a myxoid stroma & atypical vessels on histology
KEY PATHOLOGY FINDINGS
Ball-shaped or papillary/elongated mass attached to endothelial surface (of atrium) by a stalk (this is why it is mobile)
Loose myxoid stroma
Plump, stellate, or spindled cells arranged in cords
Primitive-appearing vessels
+/- hemorrhage/ hemosiderin & inflammatory cells in the background
A rarely seen feature, but good to know about...Heterologous elements (glands or extramedullary hematopoeisis) can be present in 2% of cases. This has NO clinical significance, but DON'T OVERCALL B9 GLANDS AS SOME SORT OF ADENOCARCINOMA!
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ANCILLARY STUDIES
(EX: ADDITIONAL TESTS TO CLUE YOU IN TO THE DIAGNOSIS)
Endothelial markers (CD31 & CD34) +
Calretinin +
(Helps DDx from atrial thrombus (which is Calretinin NEG)
NOTE: S100 is variably positive
NEG: Cytokeratin (but if heterologous glands are present, they will be +)
TOP DIFFERENTIAL DIAGNOSIS
ATRIAL THROMBUS: Grossly has similar appearance, but a thrombus usually is NOT MOBILE. It can have myxoid degenerative changes. Calretinin NEGATIVE
And there you have it...
Reference: Jay H. Lefkowitch. Anatomic Pathology Board Review. 2006, Elsevier Inc. pg 9.