Definition/General
Introduction:
Ovarian carcinoid tumor is a rare neuroendocrine tumor of the ovary
Accounts for <1% of ovarian tumors
May arise from teratomatous elements or de novo
Can cause carcinoid syndrome in 30% cases.
Origin:
Originates from neuroendocrine cells within teratomatous tissue or directly from ovarian stroma
Shows neuroendocrine differentiation
Produces serotonin and other hormones
Similar to carcinoids elsewhere.
Classification:
Primary ovarian carcinoid (most common)
Carcinoid arising in teratoma
Metastatic carcinoid (from GI tract)
Insular type (most common)
Trabecular type
Strumal carcinoid
Mucinous carcinoid.
Epidemiology:
Peak incidence in 5th-6th decades
Mean age 50-55 years
Unilateral in >95% cases
Carcinoid syndrome in 30%
Better prognosis than GI carcinoids.
Clinical Features
Presentation:
Pelvic mass (most common)
Carcinoid syndrome (flushing, diarrhea, wheezing) in 30%
Abdominal pain
Abdominal distension
Right heart failure (advanced cases).
Symptoms:
Abdominal/pelvic mass (80-90%)
Flushing episodes (30%)
Diarrhea (25%)
Wheezing/bronchospasm (20%)
Abdominal pain (60%)
Weight loss (advanced)
Heart palpitations.
Risk Factors:
Postmenopausal age
Previous teratomas
Family history unclear
No established environmental factors
Genetic predisposition rare
Associated with other neuroendocrine tumors (rare).
Screening:
Serum serotonin (elevated)
5-HIAA (24-hour urine)
Chromogranin A (elevated)
Neuron-specific enolase
Pelvic ultrasound
CT/MRI for staging
Octreotide scan.
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Gross Description
Appearance:
Solid, well-circumscribed mass
Yellow-tan to gray cut surface
Size ranges from 2-15 cm
Smooth capsule
Homogeneous appearance
May have cystic areas.
Characteristics:
Unilateral in >95% cases
Encapsulated appearance
Cut surface shows solid homogeneous areas
Yellow-tan color
Firm consistency
Hemorrhage and necrosis rare.
Size Location:
Variable size (1-20 cm)
Average size 6-10 cm
No specific ovarian location preference
Usually smaller than epithelial tumors
Slow growth pattern.
Multifocality:
Usually unifocal
Bilateral involvement rare (<5%)
May arise within teratomatous areas
Metastases to liver, lymph nodes in advanced cases.
Microscopic Description
Histological Features:
Uniform small cells with round nuclei
Insular pattern (most common)
Trabecular pattern
Ribbon-like arrangements
Eosinophilic cytoplasm
Salt-and-pepper chromatin.
Cellular Characteristics:
Small, uniform cells
Round to oval nuclei
Finely granular chromatin (salt-and-pepper)
Inconspicuous nucleoli
Moderate eosinophilic cytoplasm
Low mitotic rate.
Architectural Patterns:
Insular pattern (solid nests)
Trabecular pattern (cords and ribbons)
Acinar pattern (rare)
Solid pattern
Mixed patterns common.
Grading Criteria:
Well-differentiated (Grade 1): Mitoses <2/10 HPF
Moderately differentiated (Grade 2): 2-20 mitoses/10 HPF
Poorly differentiated (Grade 3): >20 mitoses/10 HPF
Necrosis indicates higher grade.
Immunohistochemistry
Positive Markers:
Chromogranin A (90-95%)
Synaptophysin (85-90%)
CD56 (80-85%)
Neuron-specific enolase (70-80%)
Serotonin (70-80%)
Cytokeratin (dot-like)
TTF-1 (variable).
Negative Markers:
AFP (negative)
Beta-hCG (negative)
Inhibin (negative)
Calretinin (negative)
WT1 (negative)
Vimentin (usually negative).
Diagnostic Utility:
Neuroendocrine markers confirm diagnosis
Chromogranin and synaptophysin essential
Serotonin positivity supports carcinoid
Distinguish from other small cell tumors
Hormone-specific staining.
Molecular Subtypes:
Similar to GI carcinoids
MEN1 mutations (rare)
Chromosomal losses (11q, 18q)
SSTR expression (somatostatin receptors)
Low mutation burden.
Molecular/Genetic
Genetic Mutations:
MEN1 mutations (rare)
Chromosomal losses (11q13, 18q21)
ATRX mutations (rare)
DAXX mutations (rare)
mTOR pathway alterations.
Molecular Markers:
Somatostatin receptor expression
Chromogranin A overexpression
Synaptophysin expression
Low Ki-67 proliferation index
p53 wild-type usually.
Prognostic Significance:
Stage most important factor
Size >10 cm worse prognosis
Mitotic rate and grade important
Carcinoid syndrome indicates advanced disease
Better prognosis than GI carcinoids.
Therapeutic Targets:
Surgical resection primary treatment
Somatostatin analogs (octreotide, lanreotide)
Targeted therapy (everolimus, sunitinib)
Peptide receptor radionuclide therapy
Chemotherapy (advanced cases).
Differential Diagnosis
Similar Entities:
Metastatic carcinoid (from GI tract)
Small cell carcinoma
Granulosa cell tumor
Stromal tumors
Neuroendocrine carcinoma.
Distinguishing Features:
Primary carcinoid: Unilateral
Better differentiated
Metastatic: Often bilateral
GI primary
Small cell: High-grade features
TTF-1 positive
Granulosa: Inhibin positive
Coffee-bean nuclei.
Diagnostic Challenges:
Primary vs metastatic distinction
GI tract evaluation essential
Grade assessment
Hormone production correlation
Staging accuracy.
Rare Variants:
Strumal carcinoid (with thyroid tissue)
Mucinous carcinoid
Goblet cell carcinoid
Large cell neuroendocrine carcinoma
Mixed neuroendocrine-epithelial.
Sample Pathology Report
Template Format
Sample Pathology Report
Complete Report: This is an example of how the final pathology report should be structured for this condition.
Specimen Information
Ovarian mass, [side], measuring [X x Y x Z] cm
Diagnosis
Carcinoid Tumor, Grade [1/2/3]
Classification
WHO Classification: Neuroendocrine Tumor, Carcinoid
Histological Features
Shows [insular/trabecular/mixed] pattern with uniform neuroendocrine cells
Grading
Grade [1/2/3]: [X] mitoses/10 HPF, [presence/absence] of necrosis
Special Studies
IHC: Chromogranin A [positive], Synaptophysin [positive], Ki-67 [X]%
Serotonin: [X] ng/mL, 5-HIAA: [X] mg/24h
Final Diagnosis
Ovarian Carcinoid Tumor, Grade [1/2/3], [Side]