[Multiple cutaneous osteomas of the face in a setting of chronic acne]. / Ostéomes cutanés multiples de la face dans un contexte d'acné chronique.

BACKGROUND: Multiple cutaneous osteomas are a rare complication of chronic inflammatory acne that often goes unrecognized. We report a case concerning a 35-year-old woman. PATIENTS AND METHODS: A 35-year-old woman had been treated for acne since the age of 22 years, as part of which she received two courses of oral isotretinoin. We noted the secondary appearance of several microcysts on the face for which the excision was very difficult. Curiously, these small formations did not contain keratin but were very callous. Histological examination revealed foci of osseous metaplasia, probably of postinflammatory origin. Treatment consisted solely of excision of the lesions. DISCUSSION: Osteoma cutis comprises two distinct groups (primary and secondary). In our case, there were multiple cutaneous osteomas of the face resulting from chronic acne. The differential diagnosis was idiopathic miliary osteomatosis of the face, but this was ruled out by the young age of the patient, the improvement of the acneiform lesions under isotretinoin (confirming the initial diagnosis of acne) and the subsequent appearance of microcysts. Although there are as yet no codified treatments, excision appears to yield good results.

Lung osteoma--a new benign lung lesion.

Extraskeletal osteomas have not been described in the lung. Tumors with osseous elements can be found, such as hamartoma and amyloid tumor, and reactive lesions such as osseous metaplasia. A 39-year-old male patient was treated for multiple myeloma and got a bone marrow transplantation 2 years and a few months before he presented with a solitary well-circumscribed tumor in the right middle lobe. The patient underwent surgical resection. The tumor presented with a fibrous capsule and consisted of mature bone trabecules. Within the tumor, fatty tissue was seen. There were small bone spicules interpreted as areas of new bone formation and appositional growth. No amyloid deposition, no immature epithelial tubules as in hamartomas, and no normal lung structure as in osseous metaplasia were seen. Within the osseous elements, a positive reaction was seen with antibodies for osteonectin, whereas the reaction for calcitonin was negative. To the best of our knowledge, this is the first case of an osteoma being reported in the lung looking like any other extraskeletal osteoma. This tumor might have been induced by circulating stem cells; however, due to autologous bona marrow transplantation, this cannot be proven.

Fibro-osseous pseudotumor of the digits: report of a case with immunohistochemical and ultrastructural studies.

A polypoid fibro-osseous nodule arising from the soft tissues of a toe of a 17 yr old man is described. Initial partial excision of the nodule led to a wrong diagnosis of pyogenic granuloma. The mistaken diagnosis was based on finding an extensively ulcerated polypoid nodule with a core of fibrovascular tissue which resembled granulation tissue. The fast growing lesion recurred twice within 4 mths following incomplete excisions. Bony destruction of the distal phalanx was noted radiologically at the second recurrence. The rare lesion is an example of fibro-osseous pseudotumor of the digits, sometimes described as pseudomalignant osseous tumor of the soft tissues. It is curable by complete local resection. The importance of recognizing this lesion lies in its potential to be confused with parosteal or extraskeletal osteosarcoma. The fast growth rate of present case led to a strong clinical suspicion of malignancy. Incomplete excisions resulted in local recurrences rendering more extensive surgery necessary. There was no further recurrence 12 mths after the last excision.

Fibro-osseous lesion with calcified spherules (cementifying fibromalike lesion) of the tibia.

The histologic and ultrastructural features of a tibial lesion strongly resembling cementifying fibroma of the jaws are described. Histologically the lesion consisted of fibrous tissue containing small calcified spherules. In some areas acellular trabeculae or islets with lobulated margins of a cementlike substance occurred. Spherules and small calcified bodies were composed of apatite crystal depositions along the collagen fibers and were often in close contact with membrane-surrounded cytoplasmic processes resembling matrix vesicles. In fibrous tissue fibroblasts, myofibroblasts, and undifferentiated cells with numerous cytoplasmic processes and intracytoplasmic microfibrils were present. The character of the cellular component of this lesion and the presence of calcified spherules arranged in a manner rarely observed in fibrous dysplasia indicate a histogenic relationship between the two lesions.

Osteofibrous dysplasia of long bones--a reactive process to adamantinomatous tissue.

The most controversial aspect of osteofibrous dysplasia (OFD) is its possible histogenetic relationship to adamantinoma of long bone. Evidence is recently beginning to accumulate that OFD may be a reactive process to regressive adamantinoma. To verify the concept, 13 lesions of OFD were studied again by immunohistochemistry for cytokeratins of different molecular masses, as well as by conventional stainings. In addition, 2 adamantinomas and 6 fibrous dysplasias of the tibia were studied for reference. A small number of spindle- or ovoid-shaped cells scattered individually in the fibro-osseous stroma showed positive reactions for cytokeratins of 55-57 kDa in 2 lesions, and for those of 45-56.5 kDa in 8 lesions of 13 OFDs, although no definite epithelial island could be detected even by immunohistochemistry. Adamantinomas also showed single cytokeratin-positive cells dispersed in fibroblastic stroma, in addition to epithelial islands positive for cytokeratins of both 55-57 kDa and 45-56.5 kDa. All cases of fibrous dysplasia were negative for cytokeratins. During the observation, no case of OFDs progressed to classic adamantinoma. The present study, demonstrating the existence of an intermediate stage between "differentiated adamantinoma" and total elimination of adamantinomatous components, gives further support for the concept that OFD is a secondary reactive process to adamantinomatous tissue. In practice, the existence of single scattered cytokeratin-immunoreactive cells in otherwise typical OFDs may not indicate the truly malignant behaviour of classic adamantinoma, unless discrete epithelioid cell nests are also found.

Multiple miliary osteoma cutis.

We describe the clinical, radiographic, histologic, and metabolic features of an unusual case of multiple miliary osteoma cutis in an otherwise healthy 57-year-old woman. Although the pathogenesis of this rarely reported entity is not fully understood, the novel application of a dynamic bone study revealed a high rate of internal bone remodeling within the lesion. This finding prompted a brief therapeutic trial of a diphosphonate, not previously reported in the treatment of this condition.