Pilomatricoma

Diagnosis

Pilomatricoma

History

11 year-old girl presenting a 3 cm exophytic indurated inflammatory lesion at the base of the neck. Initial evaluation with ultrasound and MRI demonstrated an heterogenous, highly vascularized lesion with calcifications.   Initial diagnosis was dermatofibrosarcoma protuberans.

Findings

F18-FDG PET/CT demonstrated a heterogenous exophytic lesion with SUVmax between 4.5 and 8.8. Multiples  inactive subcutaneous nodules were found.

Discussion

The lesion was removed and the diagnosis was pilomatricoma (calcifying  epithelioma  of Malherbe), with the presence of  island of epithelioid cells, shadow cells and calcifications. This benign lesion originates from the hair follicle matrix. It represents 0.12%  of all cutaneous lesions but is not infrequent in children, as the vast majority occurs in patients under the age of 21. The location of predilection is the head and neck region. Treatment is by surgical excision with low recurrence rate. Some cases imaged with FDG have been reported in adults but not yet in children.

References

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2. Pirouzmanesh A, Reinisch JF, Gonzales-Gomez I, Smith EM, Meara JG. Pilomatrixoma: a review of 346 cases. Plast Reconst Surg 2003;112:1784-1789

3. Kwon D, Grekov K, Krishnan M, Dyleski R. Characteristics of pilomatrixoma in children: a review of 137 patients. Int J Pediatr Otorhinolaryngol 2014;78:1334-1341

4. Chan JJL, Tey HL. Multiple pilomatricomas: case presentation and review of the literature. Dermatol Online J 2010 Apr 15;16(4):2

5. Park SG, Song JY, Song IG, Kim MS, Shin BS.Cutaneous Extraskeletal osteosarcoma on the scar of a previous bone graft. Ann Dermatol 2011;23:S160-S164

6. Riddle ND, Bowers JW, Bui MM, Morgan MB. Primary cutaneous osteoblastic osteosarcoma : a case report and review of the current literature. Clin Dermatol 2009;34:e879-e880

7. Bhatt MK, Sommerville R, Kumar ASR. FDG PET/CT appearance of benign pilomatricoma. Clin Nucl Med 2012;37:684-686

8. Tay JK, Nga ME, Loh KW. Pilomatricoma of the cheek: a benign tumor mimicking metastatic squamous cell carcinoma on FDG PET/CT. Am J Otolaryngol 2014;35:452-455

9. Szturz P, Rehak Z, Koukalava R, Adam Z, Mayer J. FDG-PET positive pilomatrixoma-reconsifering multicentricity in Langerhans cell histiocytosis. Nucl Med Review 2014;17:94-96