2 April 2009 - Case #142
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This case was contributed by Dr. Juan Jose Segura Fonseca, Pathology Department, Hospital San Juan de Dios, San Jose, Costa Rica.
Case #142
Clinical history:
A 17 year old woman presented with difficulty swallowing and complained of a large foreign body sensation in her mouth for several months. Physical examination revealed a bulging, rock hard tumor covered with mucosa on the floor of her mouth. Xray showed a large radioopaque tumor. It was excised and grossly was a multinodular mass of calcified tissue.
Radiology images:
Gross images:
Microscopic images:
What is your diagnosis?
Diagnosis: Osseous choristoma of the floor of the mouth (osteoma)
Discussion:
The lesion is characterized by irregular mature bone trabeculae and fibrous connective tissue, with no osteoblastic activity and no atypia. Vascular spaces reminiscent of Haversian channels are present.
A choristoma is a proliferation of tissues foreign to the site at which it is located. Choristomas of mature bone (osseous choristomas) are rare in the soft tissue of the oral cavity. They present as hard tumor-like masses in the tongue in about 85% of cases, usually in the posterior third and less commonly at other sites, such as oral mucosa, soft palate and submandibular region (Indian J Pathol Microbiol 2009;52:86, Kaohsiung J Med Sci 1998;14:727, Gerodontology 2009;26:78, Med Oral 2003;8:220, Eur Arch Otorhinolaryngol 1990;247:264, J Craniomaxillofac Surg 2006;34:57). Only a few cases have been reported in the floor of the mouth.
Osseous choristomas have been found at all ages, the youngest apparently a 2 month old girl (J Pediatr Surg 1987;22:365). They have a predilection for women (Med Oral Patol Oral Cir Bucal 2008;13:e627, Ear Nose Threat J 1998;77:316).
The differential diagnosis includes:
Surgical excision is the treatment of choice and is curative. Local recurrence is rare (Oral Surg Oral Med Oral Pathol 1991;72:337).
All cases are archived on our website. To view them sorted by case number, diagnosis or category, visit our main Case of the Month page. To subscribe or unsubscribe to Case of the Month or our other email lists, click here.
This case was contributed by Dr. Juan Jose Segura Fonseca, Pathology Department, Hospital San Juan de Dios, San Jose, Costa Rica.
Website news:
(1) We have updated the Thyroid gland chapter, with additional images and references.
(2) The Soft Tissue tumors chapter - part 1 has been reviewed by Dr. David Lucas, University of Michigan Medical Center.
(3) The Breast-nonmalignant chapter has been reviewed by Dr. Hind Nassar, Johns Hopkins Medical Institutions.
Visit and follow our Blog to see recent updates to the website.
(1) We have updated the Thyroid gland chapter, with additional images and references.
(2) The Soft Tissue tumors chapter - part 1 has been reviewed by Dr. David Lucas, University of Michigan Medical Center.
(3) The Breast-nonmalignant chapter has been reviewed by Dr. Hind Nassar, Johns Hopkins Medical Institutions.
Visit and follow our Blog to see recent updates to the website.
Case #142
Clinical history:
A 17 year old woman presented with difficulty swallowing and complained of a large foreign body sensation in her mouth for several months. Physical examination revealed a bulging, rock hard tumor covered with mucosa on the floor of her mouth. Xray showed a large radioopaque tumor. It was excised and grossly was a multinodular mass of calcified tissue.
Radiology images:
Xray
Gross images:
Microscopic images:
What is your diagnosis?
Click here for diagnosis and discussion:
Diagnosis: Osseous choristoma of the floor of the mouth (osteoma)
Discussion:
The lesion is characterized by irregular mature bone trabeculae and fibrous connective tissue, with no osteoblastic activity and no atypia. Vascular spaces reminiscent of Haversian channels are present.
A choristoma is a proliferation of tissues foreign to the site at which it is located. Choristomas of mature bone (osseous choristomas) are rare in the soft tissue of the oral cavity. They present as hard tumor-like masses in the tongue in about 85% of cases, usually in the posterior third and less commonly at other sites, such as oral mucosa, soft palate and submandibular region (Indian J Pathol Microbiol 2009;52:86, Kaohsiung J Med Sci 1998;14:727, Gerodontology 2009;26:78, Med Oral 2003;8:220, Eur Arch Otorhinolaryngol 1990;247:264, J Craniomaxillofac Surg 2006;34:57). Only a few cases have been reported in the floor of the mouth.
Osseous choristomas have been found at all ages, the youngest apparently a 2 month old girl (J Pediatr Surg 1987;22:365). They have a predilection for women (Med Oral Patol Oral Cir Bucal 2008;13:e627, Ear Nose Threat J 1998;77:316).
The differential diagnosis includes:
- Heterotopic ossification (myositis ossificans): typically occurs within muscle, and has more osteoblastic activity
- Ossifying fibroma: does affect the craniofacial skeleton, but has a proliferation of round, polyhedral or spindly cells, not seen in this case
- Dystrophic calcification: often found in old thrombi, hemartomas or keratin filled cysts but it does not resemble bone.
Surgical excision is the treatment of choice and is curative. Local recurrence is rare (Oral Surg Oral Med Oral Pathol 1991;72:337).
