Ossifying pyogenic granuloma: A rare variant usually not recognized

[Pediatric cutaneous mesenchymal tumors: How to cope with small samples?]

This review article deals with the diagnosis of superficial mesenchymal tumours in children. This is not a comprehensive review, but it focuses on the issue of diagnosis on small samples, especially on fine needle biopsies, which are more and more frequent. A selection of difficult diagnostic situations are discussed, including the case of spindle-cell tumours with variable adipocytic component, some fibrohistiocytic tumours, myofibromas, and vascular tumours. The key messages are the technical requirements in relation to the small sample size, the essential nature of clinical data in paediatric pathology and primarily the age, which is crucial not only for establishing the differential diagnosis but also for choosing the relevant ancillary techniques, and last, the utility of cytogenetics, mainly FISH, and of wisely used molecular biology techniques.

Reactionary Bone Changes in Long-Standing Pyogenic Granuloma: A Case Report

Pyogenic granuloma is a reactive lesion that is commonly seen in the skin and oral cavity. Though it is an unfortunate misnomer, being neither pyogenic nor a true granuloma, the name has been used for years. In the oral cavity, it presents as a growth mostly situated on the gingiva, but may also occur on the tongue, buccal and labial mucosa, and palate, and may even be seen in relation to dental implants. The lesion is usually bright or purple red in color, soft in consistency, relatively painless, and appears highly vascularized. Local etiologic factors are usually poor oral hygiene or chronic irritation. Histopathologically it is an inflammatory hyperplasia of the connective tissue with exuberant vascularity. Sometimes, this lesion may present with unusual histopathological patterns, which could lead to difficulty in diagnosis. Long-standing pyogenic granuloma may show histologic changes such as localized osteogenesis in the matrix of the lesion which could potentially lead to complications in the area of the lesion. This article reports a rare case with rare histopathological features in an 18-year-old female presenting with long-standing soft tissue gingival growth.

Primary cutaneous extraskeletal osteosarcoma: a series of 16 cases

Extraskeletal osteosarcoma (EOS) is a high grade soft tissue tumour characterised by the production of malignant osteoid, without attachment/involvement of underlying bone/periosteum. Rarely, EOS presents as a cutaneous tumour. The clinical behaviour of primary cutaneous EOS (PC-EOS) remains incompletely characterised. Herein we present the largest case series of PC-EOS reported to date. Sixteen PC-EOS cases from the archives/consultation files were retrieved (male:female 1:1; age 31-96 years, mean age 66 years). The tumours measured 1-10 cm (mean 3.2 cm) and were located on the lower extremity (7), head (6), upper extremity (2), and trunk (1). They consisted of pleomorphic, spindled-to-epithelioid cells, with fascicular, nodular, or sheet-like growth patterns and foci of malignant osteoid. Immunohistochemistry did not reveal specific lines of differentiation, and there was no evidence of other tumour types. A literature review was conducted to identify all well characterised cases of PC-EOS. A combined analysis of present and past cases was performed to determine overall trends in clinical characteristics and outcomes. The mean follow-up period was 23.9 months, during which 67.5% of patients experienced progression-free survival and 18% of patients died of disease. Rates of local recurrence and metastasis were 10% and 25%, respectively, approximately double past estimates. These data suggest that the prognosis of PC-EOS is less favourable than previously thought. The differential diagnosis includes benign entities (e.g., ossifying pyogenic granuloma) and malignant neoplasms with heterologous osteosarcomatous differentiation (e.g., carcinosarcoma, transdifferentiated melanoma). Wide excision remains the standard of care, and the role of chemotherapy and radiation remains inconclusive. Recognition of this rare entity can facilitate prompt diagnosis and appropriate treatment.

Ossifying pilomatricoma and a novel hypothesis for its pathogenesis: A case report and comprehensive literature review

RATIONALE

Pilomatricoma is a benign skin appendageal tumor derived from hair follicle matrix cells that commonly affects the head, neck, and upper extremities of the pediatric population. Since the original tumor description, diverse variants have been reported in the literature. Pilomatricoma with florid osseous metaplasia is described as an ossifying pilomatricoma and is recognized as a distinct variant of this benign tumor. However, the pathogenesis of this variant remains unclear. In this study, we present an uncommon case of ossifying pilomatricoma and address the pathogenesis of metaplastic ossification through a comprehensive literature review.

PATIENT CONCERNS

A 14-year-old boy presented with an asymptomatic protuberant mass in the preauricular region.

DIAGNOSIS

Based on its clinicopathological features, we diagnosed the lesion as an ossifying pilomatricoma.

INTERVENTIONS AND OUTCOMES

The lesion was surgically removed under local anesthesia. The postoperative course was uneventful during the 6-month postoperative follow-up.

LESSONS

We suggest that metaplastic ossification in ossifying pilomatricoma represents another feature of foreign body reaction to keratinous materials containing shadow cells in old lesions and a walling-off phenomenon to prevent exposure of surrounding tissues to keratinous materials.