Case 45
- Wangpan Shi
- Feb 11
- 2 min read
A 85-year-old female with a right lower lobe lung mass.
What's the morphology impression of big category?
A: Primary lung benign neoplasm
B: Primary lung malignant neoplasm
C: Metastatic malignancy
D: Primary or metastatic carcinoma
E: Primary or metastatic sarcoma
The tumor was found to be positive for stains below; while negative for pan-keratin, TTF-1.
ER 
CD56 
CD99 
Inhibin Based on the morphology and immunostains that are positive; What is the diagnosis?
A: Well differentiated carcinoid
B: Small cell carcinoma
C: Desmoplastic small round cell tumor
D: Metastatic carcinoma with sex cord differentiation
E: Uterine tumors resembling ovarian sex cord tumors
Answer
This is a case of metastatic UTROSCT, a tumor primarily in the uterus. It can show various morphology including sheets, cords, nests, insulae, trabeculae, tubules; sometimes with a retiform appearance. It's a tumor with uncertain malignant potential and this case represents the metastatic nature.
Immunohistochemistry |
Polyphenotypic profile with variable positivity for: - Sex cord markers: Inhibin, calretinin, WT1, CD56, CD99, SF1, FOXL2, melan-A - Epithelial markers - Hormonal markers: ER, PR - Smooth muscle markers: Actin, desmin, h-caldesmon - CD10 |
The molecular findings are summarized below:
Feature | Details |
Hypothesized Origin | Pluripotent mesenchymal cells, endometrial stromal cells, or displaced ovarian sex cord cells (Pathogenesis uncertain) |
Genetic Rearrangements | ESR1 or GREB1 rearrangements with various partners |
Common Fusion Partners | - NCOA1, NCOA2, NCOA3 (nuclear receptor coactivators) - CTNNB1 (β-catenin) - NR4A3 (nuclear receptor) - SS18 (chromatin modifier) |
Molecular Exclusion | Does not harbor: - Low-grade endometrial stromal sarcoma (LG-ESS): JAZF1-SUZ12 fusion - Adult granulosa cell tumor: FOXL2 alterations - Sertoli–Leydig cell tumor: DICER1 alterations |
Case credit: UCSD Pathology
Author: Wangpan Jackson Shi, MD
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