Mediastinum
Thymic neuroendocrine tumor
Carcinoid tumor
Author: Hanni Gulwani, M.B.B.S.
Last author update: 1 December 2012
Last staff update: 19 September 2023
Copyright: 2003-2024, PathologyOutlines.com, Inc.
PubMed Search: Carcinoid tumor mediastinum
Table of Contents
Definition / general | Terminology | Sites | Diagrams / tables | Clinical features | Prognostic factors | Case reports | Treatment | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Electron microscopy description | Differential diagnosis | Spindle cell carcinoid of thymusCite this page: Gulwani H. Carcinoid tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/mediastinumcarcinoid.html. Accessed April 25th, 2024.
Definition / general
- Similar to carcinoid tumors elsewhere
Terminology
- Also called well differentiated neuroendocrine carcinoma
Sites
- Usually of thymic origin in anterior mediastinum, occasionally in middle or posterior mediastinum
Diagrams / tables
Images hosted on other servers:
Features of 4 patients
(tables 1 and 3)
Clinical features
- Mean age 48 years old, 80% men
- 20% occur in MEN1 or MEN2 patients
- One - third have paraneoplastic Cushing syndrome, syndrome of inappropriate antidiuretic hormone, Eaton-Lambert syndrome or rarely PTH production (Ann Thorac Surg 2002;73:675)
- Coexisting carcinoid syndrome is very unusual
- Behavior similar to atypical carcinoid at other sites; must be considered to have metastatic potential with metastasis to mediastinal lymph nodes, bone, liver, skin
- May recur after up to 10 years
Prognostic factors
- Poor prognosis (Korean J Pathol 2012;46:221)
- Poor prognostic factors: ectopic ACTH production or association with MEN syndromes
- 5 year survival: 70% without endocrinopathy versus 35% with endocrinopathy
Case reports
- 41 year old woman with tumor arising in a thymic bronchogenic cyst (Pathol Int 2012;62:49)
- 45 year old woman with giant carcinoid tumour originating from posterior mediastinum (Indian J Chest Dis Allied Sci 2010;52:241)
- 62 year old man with anterior mediastinal mass - atypical carcinoid (Case of the Week #278)
- 68 year old man with thymic carcinoid tumour arising within thymolipoma (BMJ Case Rep 2010 Nov 2;2010)
- With mucinous stroma (Ann Diagn Pathol 2006;10:114)
Treatment
- Aggressive, presents at advanced stage; complete surgical resection with postoperative radiotherapy to tumor bed is recommended (Interact Cardiovasc Thorac Surg 2010;11:732)
- Radiation therapy and chemotherapy are ineffective
Gross description
- Well circumscribed but unencapsulated, firm, gray-pink, fleshy, gritty on cut section, hemorrhage, necrosis, no internal fibrous septa
Microscopic (histologic) description
- Organoid pattern with islands, ribbons, festoons, trabeculae, rosettes of small round cells with minimal cytoplasm, salt and pepper chromatin, no / rare mitotic activity
- Cellular nests may become detached from septa during processing and contain foci of central geographic necrosis with dystrophic calcification
- Marked vascularization, frequent angiolymphatic invasion, may have amyloid type stroma, sclerotic (desmoplastic type) stroma, melanin pigment, mucin
- May coexist with sarcomatoid carcinoma, thymoma, thymic cyst
- No lymphocytes, no perivascular spaces
Microscopic (histologic) images
Case #278
Atypical carcinoid
Atypical carcinoid -
AE1 / AE3
Atypical carcinoid - synaptophysin
Images hosted on other servers:
Figures a - d
Atypical carcinoid
Various stains
Positive stains
- Keratin, EMA, NSE, synaptophysin, CD57 / Leu7, chromogranin A, variable peptides, variable CEA
Negative stains
Electron microscopy description
- Numerous dense core neurosecretory granules, perinuclear whorls of intermediate filaments, intercellular junctions
- No complex nucleoli, no premelanosomes, no branching surface microvilli, no complex desmosomes, no tonofilaments
Differential diagnosis
- Paraganglioma:
- Parathyroid carcinoma:
- PAS+ diastase sensitive, PTH+
- Thymoma:
- Carcinoid tumor is frequently misclassified as thymoma (Arch Pathol Lab Med 2006;130:1612)
Spindle cell carcinoid of thymus
Clinical features
Case reports
Gross description
Microscopic (histologic) description
Positive stains
Electron microscopy description
- Very rare
- May cause death
- Associated with MEN1, syndrome of inappropriate antidiuretic hormone secretion
- Aggressive clinical behavior (Mod Pathol 1999;12:587)
Case reports
- 24 year old man with ectopic ACTH secretion and Cushing syndrome (Histopathology 2002;40:159)
Gross description
- Tan-brown, well circumscribed, encapsulated, 2 - 15 cm
Microscopic (histologic) description
- Fascicles of plump spindle cells separated by thin fibrovascular septa
- Amphophilic and granular cytoplasm, finely dispersed chromatin
- Frequent mitotic figures, frequent focal necrosis
- No / vague organoid pattern, no prominent nucleoli
Positive stains
Electron microscopy description
- Neurosecretory granules
