Hamartoma overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Maria Fernanda Villarreal, M.D. [2]
Overview
A hamartoma (from Greek hamartion “bodily defect”) is a focal malformation that resembles a neoplasm in the tissue of its origin. Hamartoma is a non-malignant tumor, and it grows at the same rate as the surrounding tissues. It is composed of an overgrowth of mature cells and tissues that normally occur in the affected area.[1] They emerge in many different parts of the body and are most often asymptomatic and undetected unless seen on an image taken for another reason (incidentaloma). The most common hamartomas occur in the lungs. About 5–8% of all solitary lung nodules, and about 75% of all benign lung tumors, are hamartomas. They almost always arise from connective tissue and are generally formed of cartilage, fat, and connective tissue cells, although they may include many other types of cells.[2] Hamartomas must be differentiated from other diseases that cause abnormal tissue growth and calcifications, such as sarcoidosis, calcified metastases, and PTEN hamartoma tumor syndrome.[3] Surgery is the mainstay of treatment for hamartomas.[4]
Historical Perspective
Hamartomas were first described by Eugen Albrecht, a German pathologist, in 1904.[5]
Classification
Hamartomas may be classified into different types based on their location, such as; lung (most common), heart, hypothalamus, kidneys, or spleen. Other classifications can consider lesion class, dividing hamartomas into 4 different categories, such as; Bone-forming, cartilage-forming, fiber-forming and benign non–matrix-forming.[6]
Pathophysiology
Hamartomas arise from connective tissue and are generally formed of cartilage, fat, and connective tissue cells, although they may include many other types of cells. They can be located in lung (most common), heart, hypothalamus, kidneys, or spleen. The pathogenesis consists in the disorganized replication of normal tissue cells. There are many genetic syndromes that cause multiple hamartomas, such as; Peutz-Jeghers syndrome, PTEN hamartoma tumor syndrome, and Cowden’s syndrome. Genes involved in the pathogenesis of harmatomatous syndromes include; BMPR1A, SMAD4, PTEN and STK11.[7][6]
Causes
The causes of hamartomas have not been identified.[4][8]
Epidemiology and Demographics
The prevalence of pulmonary hamartoma is approximately 0.25% in general population. The prevalence of other hamartomas remains unknown.[9][10] Hamartomatous tumors are usually first diagnosed among adult patients and are uncommon in children.[9] Overall, all hamartomas affect males more commonly than females.[9]
Risk Factors
The most potent risk factor in the development of multiple hamartomas is familial inheritance syndromes, such as: Cowden disease, Peutz-Jeghers syndrome, and PTEN related syndromes.[3]
Screening
Screening for sporadic hamartomas is not recommended. However, in case of familial inheritance hamartoses screening at early age is recommended.[3]
Differential diagnosis
Hamartomas must be differentiated from other diseases that cause abnormal tissue growth and calcifications, such as sarcoidosis, calcified metastases, and PTEN hamartoma tumor syndrome.[3]
Natural History, Complications and Prognosis
If left untreated, hamartomas normally grow slowly and may progress to develop a considerable size, however pulmonary hamartomas have low or no malignant potential. Nevertheless, it is essential to rule out the presence of cancer. Common complications of hamartomas will depend on the location and size. Prognosis is generally regraded as excellent.[11]
Diagnosis
Staging
There is no established system for the staging of hamartomas.
History and Symptoms
Hamartomas are usually asymptomatic. However, in some cases such as, hypothalamic hamartomas and pulmonary hamartomas, symptoms may be more noticeable. In hypothalamic hamartomas, gelastic seizures, visual problems, early onset of puberty, and behavioral problems are the most reported.[12] On the other hand, symptoms of pulmonary hamartoma may result as a respiratory obstruction and include chronic cough, hemoptysis, or fever.[12] It is important to obtain the history about familial inheritance, as it provides insight into the associated conditions.
Physical examination
Patients with hamartoma usually have a normal appearance. Physical examination shows no remarkable findings.[12]
Laboratory tests
There are no diagnostic laboratory findings associated with hamartoma. However, in some cases complete blood count, serum electrolytes, urea, and alkaline phosphatase levels may be indicated if the tumor becomes symptomatic.[13]
Chest X-Ray
On chest x-ray, lung hamartomas have a popcorn-like appearance.[4]
CT
On CT scan, hamartoma is characterized by focal collections of fat, a lesion with a smooth edge, and collections of fat alternating with foci of calcification.[14]
MRI
On MRI, hamartoma is characterized by a heterogeneous signal in T1 and high signal due to fat and cartilaginous components in T2.[12]
Ultrasound
On ultrasound, splenic hamartomas are hyperechoic solid masses, with or without cystic changes in ultrasonogram, and are hypervascular in both color Doppler ultrasound and angiogram. [15]
Other Diagnostic Studies
Bronchoscopy may be useful to obtain biopsy and evaluate symptomatic bronchial hamartomas.[14]
Treatment
Medical therapy
There is no known medical therapy for hamartomas.[4]
Surgery
Surgery is the mainstay for hamartomas.[4]
Primary Prevention
There is no established method for prevention of hamartomas.
Secondary Prevention
Secondary prevention strategies following hamartomas include periodical imaging surveillance with CT scan.[16]
References
- ↑ Mitchell, Richard; Kumar, Vinay; Fausto, Nelson; Abbas, Abul K.; Aster, Jon (2011). Pocket Companion to Robbins & Cotran Pathologic Basis of Disease (8th ed.). Elsevier Saunders. pp. 147. ISBN 978-1416054542.
- ↑ Zakharov V, Schinstine M (2008). "Hamartoma of the lung". Diagn. Cytopathol. 36 (5): 331–2. doi:10.1002/dc.20790. PMID 18418855.
- ↑ 3.0 3.1 3.2 3.3 Brown K, Mund DF, Aberle DR, Batra P, Young DA (1994). "Intrathoracic calcifications: radiographic features and differential diagnoses". Radiographics. 14 (6): 1247–61. doi:10.1148/radiographics.14.6.7855339. PMID 7855339.
- ↑ 4.0 4.1 4.2 4.3 4.4 Hamartomas. Wikipedia https://en.wikipedia.org/wiki/Hamartoma Accessed on December 08, 2015
- ↑ Ober WB (1978). "Selected items from the history of pathology: Eugen Albrecht, MD (1872-1908): hamartoma and choristoma". Am. J. Pathol. 91 (3): 606. PMC 2018308. PMID 350057.
- ↑ 6.0 6.1 Kumar V, Abbas AK, Aster JC. Robbins Basic Pathology. Elsevier Health Sciences; 2012.
- ↑ Stojcev Z, Borun P, Hermann J, et al. Hamartomatous polyposis syndromes. Hered Cancer Clin Pract. 2013;11(1):4.
- ↑ Mester J, Charis E. PTEN hamartoma tumor syndrome. Handb Clin Neurol. 2015;132:129-37.
- ↑ 9.0 9.1 9.2 Hansen CP, Holtveg H, Francis D, Rasch L, Bertelsen S (1992). "Pulmonary hamartoma". J. Thorac. Cardiovasc. Surg. 104 (3): 674–8. PMID 1513155.
- ↑ Nguyen D, Singh S, Zaatreh M, Novotny E, Levy S, Testa F, Spencer SS (2003). "Hypothalamic hamartomas: seven cases and review of the literature". Epilepsy Behav. 4 (3): 246–58. PMID 12791326.
- ↑ Marchiori E, Souza AS, Franquet T, Müller NL (2005). "Diffuse high-attenuation pulmonary abnormalities: a pattern-oriented diagnostic approach on high-resolution CT". AJR Am J Roentgenol. 184 (1): 273–82. doi:10.2214/ajr.184.1.01840273. PMID 15615988.
- ↑ 12.0 12.1 12.2 12.3 Hypothalamic hamartoma. Dr Donna D'Souza et al. Radiopedia.http://radiopaedia.org/articles/pulmonary-hamartoma-1 Accessed on December 09, 2015
- ↑ Vlachou P, Fagkrezos D, Tzivelopoulou A, Kyriakopoulou G, Maniatis P, Triantopoulou C, Papailiou J (2015). "A rare case of a splenic hamartoma in a patient with a huge palpable abdominal mass: a case report". J Med Case Rep. 9: 4. doi:10.1186/1752-1947-9-4. PMC 4405829. PMID 25626774.
- ↑ 14.0 14.1 Gaerte SC, Meyer CA, Winer-Muram HT, Tarver RD, Conces DJ (2002). "Fat-containing lesions of the chest". Radiographics. 22 Spec No: S61–78. doi:10.1148/radiographics.22.suppl_1.g02oc08s61. PMID 12376601.
- ↑ Splenic hamartoma. Dr Henry Knipe http://radiopaedia.org/articles/splenic-hamartoma Accessed on December,08 2016
- ↑ Amini B, Huang SY, Tsai J, Benveniste MF, Robledo HH, Lee EY (2013). "Primary lung and large airway neoplasms in children: current imaging evaluation with multidetector computed tomography". Radiol. Clin. North Am. 51 (4): 637–57. doi:10.1016/j.rcl.2013.04.005. PMID 23830790.