Homayoon Rahbari

Basal Cell Epitheliomas in Usual and Unusual Sites

2,126 consecutively diagnosed basal cell epitheliomas (BCE) were studied for unusual sites of occurrence. A small number of BCE occurred in unexpected locations and presented some difficulty in clinical diagnosis.

Basal cell epithelioma (carcinoma) in children and teenagers.

Among over 390,000 routine dermatopathologic specimens there were 85 cases diagnosed as basal cell epithelioma (carcinoma) (BCE) in persons 19 years old or younger. This number was refined to 40 cases de novo BCE in children and teenagers. Basal cell epithelioma unrelated to other conditions is rare in the young and it should be differentiated from similar fibroepithelial growths.

Trichoadenoma of Nikolowski.

Trichoadenoma of Nikolowski is a rare benign tumor of the skin with hair follicle‐like direction of differentiation. This tumor is less mature than trichofolliculoma and more differentized than tri‐choepithelioma. Probably because of its rarity it has not been a well recognized tumor. We are reporting on eight cases of trichoadenoma to further define this benign growth.

Adnexal displacement and regression in association with histiocytoma (dermatofibroma)

The literature about the changes occurring in histiocytomas mentions only the possibility of induction of primitive pilosebaceous structures and basal cell epithelioma‐like lesions by the histiofibrocytic growth. We suggest here that the histopathologic findings arc indicative of regressive changes of the pre‐existing cutaneous adnexa resulting in the formation of basal cell epithelioma‐like structures.

Trichoepithelioma and Pigmented Nevus. A Combined Malformation

The occasional occurrences of combined hamartomas composed of nevus cell nevi and adnexal tumors are not chance happenings. Pigmented nevi are malformations consisting of nevus cells together with various connective tissue and epithelial components. The proliferation of these components results in the combined malformations, whose occurrence, we believe, is more supporting evidence for the idea that pigmented nevi may have other components besides nevus cells.

Histochemical differentiation of localized morphea-scleroderma and lichen sclerosus et atrophicus.

Dermatologic literature has debated the occurrence of concommitant morphea‐scleroderma (M‐S) and lichen sclerosus et atrophicus (LSA) for sometime. Presentation of a case which has the appearance of both M‐S and LSA creates a diagnostic dilemma frequently unresolved even by histopathology. Routine hematoxylin and eosin stained sections may add to the confusion and the difficulty of the differentiation, but examination for the presence or absence of elastic fibers in the upper corium of the lesions affords a definitive separation of these two conditions.

Development of proliferating trichilemmal cyst in organoid nevus: Presentation of two cases

One of the two types of complications that may occur with organoid nevus (nevus sebaceus) is the category of brain malformations and seizure disorders. The second type is the late occurrence of various epithelial growths that are usually observed to develop in long-standing organoid nevi. Among these later-occurring lesions, we are describing the occurrence of proliferating trichilemmal cysts in association with organoid nevi.

Rhodamin B Stain for Keratin: Evaluation of its Specificity and its Application in Dermal Pathology

We used Rhodamin B stain in sections of normal skin, benign and malignant epithelial tumors and dermatoses. Keratin staining was uneven and showed variation in different lesions. While tricho‐hyalin of the anagen hair follicle stained with intensity, keratohyalin granules failed to show similar reaction.

Acid orcein and Giemsa stain. Modification of a valuable stain for dermatologic specimens.

Heating the skin biopsy section in the Giemsa solution at 60° C for 1/2 h shortens the staining time required for the acid orcein and Giemsa technique and improves the color contrast.

Pilary Complex Carcinoma: An Adnexal Carcinoma of the Skin with Differentiation towards the Components of the Pilary Complex

We report twelve cases with a distinctive form of adnexal carcinoma occurring most commonly over the head and neck of relatively old individuals. The growth was single in all cases, deep dermal in location, and consisted of massive proliferation of small basaloid cells with only occasional connection with the surface epidermis. The basaloid tumor masses showed only a few areas of palisading of their outer cell nuclei and occasional retraction space formation. The neoplasm revealed scattered areas of trichilemmal and epidermoid keratinization, foci of sebaceous, and areas of sweat ductal differentiation indicating participation of various components of the pilary complex.