Ovary
Sex cord stromal tumors
Microcystic stromal tumor
Last author update: 1 March 2016
Last staff update: 19 October 2020
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PubMed Search: Microcystic stromal tumor [title] ovary
Table of Contents
Definition / general | Essential features | Epidemiology | Pathophysiology / etiology | Clinical features | Diagnosis | Laboratory | Prognostic factors | Case reports | Treatment | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Electron microscopy description | Molecular / cytogenetics description | Differential diagnosisCite this page: Abdulfatah E, Ali-Fehmi R, Bandyopadhyay S, Shi DP. Microcystic stromal tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/ovarytumormicrocysticstromal.html. Accessed September 25th, 2023.
Definition / general
- Benign ovarian neoplasm of presumed stromal origin
- First described by Irving and Young in 2009 (Am J Surg Pathol 2009;33:367)
Essential features
- Features to establish a diagnosis of microcystic stromal tumor in well sampled specimens include:
- A microcystic pattern and regions with lobulated cellular masses with intervening hyalinized, fibrous stroma
- No morphologic features enabling any other specific diagnosis in the sex cord stromal category
- No epithelial elements
- No teratomatous or other germ cell elements (Am J Surg Pathol 2009;33:367)
Epidemiology
- Mean age of 45 years (range 26 - 63 years)
Pathophysiology / etiology
- Deregulation of the Wnt/beta-catenin pathway has been suggested to play a role in the pathogenesis of microcystic stromal tumor (Am J Surg Pathol 2011;35:1429)
- The ulrastructural features of this tumor support a stromal cell origin (Ultrastruct Pathol 2014;38:261)
Clinical features
- Patients present with symptoms attributable to a pelvic mass
- Not associated with manifestations related to hormonal excess
- Usually unilateral
- Often < 5 - 10 cm (range 2 - 27 cm)
Diagnosis
- Histologic recognition, confirmed by immunophenotype
Laboratory
- No specific laboratory findings
Prognostic factors
- Benign behavior, no reports of recurrence or malignant transformation
Case reports
- 32 and 41 year old women with β-catenin S33C mutation (Am J Surg Pathol 2011;35:1429)
- 47 year old woman with overlap of microcystic stromal tumor and primary solid pseudopapillary neoplasm (Int J Clin Exp Pathol 2015;8:11792)
- 50 year old woman (Int J Gynecol Pathol 2015;34:541)
- Ovarian microcystic stromal tumor (Ultrastruct Pathol 2014;38:261)
Treatment
- Excision results in complete cure
Gross description
- Well demarcated, solid-cystic tumor, however either solid or cystic areas can predominate
- Solid component has tan-white cut surface
- Foci of hemorrhage or necrosis can be present
Microscopic (histologic) description
- Distinctive triad of histologic features:
- Microcysts: small round / oval cystic spaces that may coalesce to larger irregular channels
- Solid cellular regions
- Hyalinized fibrous stroma
- Cells have moderate, finely granular eosinophilic cytoplasm, bland round/oval nuclei with fine chromatin and indistinct nucleoli
- Foci of bizarre nuclei may be seen, low mitotic rate (up to 2/10HPF)
Microscopic (histologic) images
Images hosted on other servers:
Well demarcated mass
CD10, CD56, β-catenin, WT1, PR
Positive stains
- CD10, vimentin, focal cytokeratin (25%)
- β-catenin, FOXL2, WT1, Cyclin D1, SF1 (Am J Surg Pathol 2015;39:1420)
Negative stains
Electron microscopy description
- Tumor cells with predominantly spindle and stellate morphology with fewer epithelioid cells, arranged in a loose "microcystic" pattern
- The cytoplasm shows intermediate filaments and variable amount of other organelles (Ultrastructural Pathol 2014;38:261)
- The centrally placed nuclei are round with thin nuclear membranes and dispersed euchromatin
- Some nuclei have prominent nucleoli
Molecular / cytogenetics description
- Missense point mutations in exon 3 of CTNNB1 was recently described (Am J Surg Pathol 2015;39:1420)
Differential diagnosis
- Adult granulosa cell tumor: oval cells with nuclear grooves, Call-Exner bodies, positive for inhibin and calretinin and FOXL2 gene mutation
- Sertoli-Leydig tumor: positive for inhibin and calretinin
- Steroid cell tumor: androgenic manifestations, positive for inhibin and calretinin
- Thecoma: older women, estrogenic manifestations, positive for inhibin, calretinin and CD56
- Yolk sac tumor: larger size, elevated serum AFP, Schiller-Duval bodies; positive for AFP immunostain
