Fibrous hamartoma of infancy

Changed by Zishan Sheikh, 1 Apr 2018

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Fibrous hamartoma of infancy is a rare benign tumour of the subcutaneous tissues ~~see~~seen in children. More than 90% of cases present in the first year of life with up to 25% being congenital ¹.

Epidemiology

There is a reported male:female ratio of 2:1 but the exact incidence is unknown ².

Clinical features

Presentation is usually with a ~~lump~~painless, ~~most~~mobile lump that is usually less than 5 cm. It is commonly around the trunk or extremities though it can occur in the head and neck regions as well. ~~More than 90% of cases present in the first year of life with up to 25% being congenital.~~

Pathology

Histologically these lesions are comprised of three distinct tissue/cell components ^1,2:

intersecting trabeculae of mature fibrous tissue
islands of immature mesenchymal tissue
mature adipose tissue
- can predominant lesions

The precise mixture of the various components in individual tumours determine their imaging characteristics.

Radiographic features

US

heterogenous hyperechogenecity
serpentine intervening hypoechoic portions
margins well defined or lobulated
vascularity is minimal if present

MRI

Features include ⁴:

fatty component is T1 and T2 hyperintense
- often predominates the lesion
fibrous tissue is T1 and T2 hypointense
- often arranged in intersecting trabeculae
- isointense to muscle
- some lesions can have large fibrous component

The presence of fat containing subcutaneous mass with intersecting bands of fibrous signal tissue in the appropriate age group is highly suggestive of the diagnosis. When closely apposed to the deeper muscle or fascial planes it may be difficult to differentiate from more aggressive soft tissue tumours.

Treatment and prognosis

Local excision is usually curative since recurrence is uncommon.

Differential diagnosis

benign
- involuting haemangioma
malignant

-<p><strong>Fibrous hamartoma of infancy</strong> is a rare benign tumour of the subcutaneous tissues see in children.</p><h4>Clinical features</h4><p>Presentation is usually with a lump, most commonly around the trunk or extremities though it can occur in the head and neck regions as well. More than 90% of cases present in the first year of life with up to 25% being congenital.</p><h4>Pathology</h4><p> </p><h4>Radiographic features</h4><h5>US</h5><p> </p><h5>MRI</h5><p> </p><p> </p>
+<p><strong>Fibrous hamartoma of infancy</strong> is a rare benign tumour of the subcutaneous tissues seen in children. More than 90% of cases present in the first year of life with up to 25% being congenital <sup>1</sup>.</p><h4>Epidemiology</h4><p>There is a reported male:female ratio of 2:1 but the exact incidence is unknown <sup>2</sup>.</p><h4>Clinical features</h4><p>Presentation is usually with a painless, mobile lump that is usually less than 5 cm. It is commonly around the trunk or extremities though it can occur in the head and neck regions as well. </p><h4>Pathology</h4><p>Histologically these lesions are comprised of three distinct tissue/cell components <sup>1,2</sup>:</p><ul>
+<li>intersecting trabeculae of mature fibrous tissue</li>
+<li>islands of immature mesenchymal tissue</li>
+<li>mature adipose tissue<ul><li>can predominant lesions</li></ul>
+</li>
+</ul><p>The precise mixture of the various components in individual tumours determine their imaging characteristics.</p><h4>Radiographic features</h4><h5>US</h5><ul>
+<li>heterogenous hyperechogenecity</li>
+<li>serpentine intervening hypoechoic portions</li>
+<li>margins well defined or lobulated</li>
+<li>vascularity is minimal if present</li>
+</ul><h5>MRI</h5><p>Features include <sup>4</sup>:</p><ul>
+<li>fatty component is T1 and T2 hyperintense<ul><li>often predominates the lesion</li></ul>
+</li>
+<li>fibrous tissue is T1 and T2 hypointense<ul>
+<li>often arranged in intersecting trabeculae </li>
+<li>isointense to muscle</li>
+<li>some lesions can have large fibrous component</li>
+</ul>
+</li>
+</ul><p>The presence of fat containing subcutaneous mass with intersecting bands of fibrous signal tissue in the appropriate age group is highly suggestive of the diagnosis. When closely apposed to the deeper muscle or fascial planes it may be difficult to differentiate from more aggressive soft tissue tumours.</p><h4>Treatment and prognosis</h4><p>Local excision is usually curative since recurrence is uncommon.</p><h4>Differential diagnosis</h4><ul>
+<li>benign<ul><li>involuting haemangioma</li></ul>
+</li>
+<li>malignant<ul>
+<li><a href="/articles/fibrosarcoma">fibrosarcoma</a></li>
+<li><a href="/articles/rhabdomyosarcoma">rhabdomyosarcoma</a></li>
+<li><a href="/articles/juvenile-fibromatosis">juvenile fibromatosis</a></li>
+</ul>
+</li>
+</ul>

References changed:

1. Laffan EE, Ngan BY, Navarro OM. Pediatric soft-tissue tumors and pseudotumors: MR imaging features with pathologic correlation: part 2. Tumors of fibroblastic/myofibroblastic, so-called fibrohistiocytic, muscular, lymphomatous, neurogenic, hair matrix, and uncertain origin. (2009) Radiographics : a review publication of the Radiological Society of North America, Inc. 29 (4): e36. <a href="https://doi.org/10.1148/rg.e36">doi:10.1148/rg.e36</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/19448107">Pubmed</a> <span class="ref_v4"></span>
2. Saab ST, McClain CM, Coffin CM. Fibrous hamartoma of infancy: a clinicopathologic analysis of 60 cases. (2014) The American journal of surgical pathology. 38 (3): 394-401. <a href="https://doi.org/10.1097/PAS.0000000000000104">doi:10.1097/PAS.0000000000000104</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/24525510">Pubmed</a> <span class="ref_v4"></span>
2. Saab ST, McClain CM, Coffin CM. Fibrous hamartoma of infancy: a clinicopathologic analysis of 60 cases. (2014) The American journal of surgical pathology. 38 (3): 394-401. <a href="https://doi.org/10.1097/PAS.0000000000000104">doi:10.1097/PAS.0000000000000104</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/24525510">Pubmed</a> <span class="ref_v4"></span>
3. Lee S, Choi YH, Cheon JE, Kim MJ, Lee MJ, Koh MJ. Ultrasonographic features of fibrous hamartoma of infancy. (2014) Skeletal radiology. 43 (5): 649-53. <a href="https://doi.org/10.1007/s00256-014-1838-1">doi:10.1007/s00256-014-1838-1</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/24535316">Pubmed</a> <span class="ref_v4"></span>
3. Lee S, Choi YH, Cheon JE, Kim MJ, Lee MJ, Koh MJ. Ultrasonographic features of fibrous hamartoma of infancy. (2014) Skeletal radiology. 43 (5): 649-53. <a href="https://doi.org/10.1007/s00256-014-1838-1">doi:10.1007/s00256-014-1838-1</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/24535316">Pubmed</a> <span class="ref_v4"></span>
4. Stensby JD, Conces MR, Nacey NC. Benign fibrous hamartoma of infancy: a case of MR imaging paralleling histologic findings. (2014) Skeletal radiology. 43 (11): 1639-43. <a href="https://doi.org/10.1007/s00256-014-1940-4">doi:10.1007/s00256-014-1940-4</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/24970668">Pubmed</a> <span class="ref_v4"></span>
4. Stensby JD, Conces MR, Nacey NC. Benign fibrous hamartoma of infancy: a case of MR imaging paralleling histologic findings. (2014) Skeletal radiology. 43 (11): 1639-43. <a href="https://doi.org/10.1007/s00256-014-1940-4">doi:10.1007/s00256-014-1940-4</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/24970668">Pubmed</a> <span class="ref_v4"></span>
2. Lee S, Choi YH, Cheon JE, Kim MJ, Lee MJ, Koh MJ. Ultrasonographic features of fibrous hamartoma of infancy. (2014) Skeletal radiology. 43 (5): 649-53. <a href="https://doi.org/10.1007/s00256-014-1838-1">doi:10.1007/s00256-014-1838-1</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/24535316">Pubmed</a> <span class="ref_v4"></span>
3. Stensby JD, Conces MR, Nacey NC. Benign fibrous hamartoma of infancy: a case of MR imaging paralleling histologic findings. (2014) Skeletal radiology. 43 (11): 1639-43. <a href="https://doi.org/10.1007/s00256-014-1940-4">doi:10.1007/s00256-014-1940-4</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/24970668">Pubmed</a> <span class="ref_v4"></span>
4. Saab ST, McClain CM, Coffin CM. Fibrous hamartoma of infancy: a clinicopathologic analysis of 60 cases. (2014) The American journal of surgical pathology. 38 (3): 394-401. <a href="https://doi.org/10.1097/PAS.0000000000000104">doi:10.1097/PAS.0000000000000104</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/24525510">Pubmed</a> <span class="ref_v4"></span>