Amir H. Mehregan

The dermatopathology of Cowden's syndrome*

During the past 2 years we have studied eighty‐nine biopsy specimens from nineteen patients with Cowdens syndrome. Among fifty‐three facial lesions, twenty‐nine were trichilemmomas. Twenty‐ three of the others were consistent with trichilemmoma, showed a non‐specific benign verrucous acanthoma, or were not diagnostic; one was a bluenaevus. All fourteen oral mucosal biopsy specimens were benign fibromas. Nineteen of twenty‐two biopsy specimens from the hands and feet showed the pattern of benign keratosis. Multiple trichilemmomas were found in all patients with Cowdens syndrome, but at times several biopsy specimens were required before a diagnostic picture was un‐ covered. All patients with multiple facial trichilemmomas were found to have Cowdens syndrome. The combination of multiple facial trichilemmomas, oral fibromas, and benign acral keratoses enables one to diagnose Cowdens syndrome at a stage before serious internal complications develop.

Malignant transformation of eccrine tumors

Malignant transformation occurred in pre‐existing sweat gland tumors in 7 patients. Three lesions showed an histologic pattern of eccrine spiradenoma, 2 eccrine poroma, one cylindroma and one papillary eccrine adenoma. Malignant transformation was histologically characterized by the presence of solid tumor areas populated with large cells having irregularly shaped nuclei and mitotic figures. There were multiple foci of squamous metaplasia, areas of loss of basement membrane and invasion of the surrounding connective tissue.

Basaloid follicular hamartoma: three cases with localized and systematized unilateral lesions

Two patients having a localized plaque of alopecia on the scalp, and one with a systematized unilateral epithelial nevus exhibited a histologically distinctive form of follicular hamartoma. In the affected areas individual hair follicles were replaced, or were associated with solid strands and branching cords of undifferentiated basaloid cells, filled in between by fibrous stroma resembling either a miniature premalignant fibroepithelial tumor of Pinkus, a small trichoepithelioma, or a basal cell epithelioma. The relation between these 3 patients and cases reported as linear unilateral basal cell nevus with comedones and generalized hair follicle hamartoma associated with myasthenia gravis is discussed.

Chronic Lupoid Leishmaniasis: Evaluation by Polymerase Chain Reaction

BACKGROUNDnThe cutaneous lesions in chronic lupoid leishmaniasis resemble those of lupus vulgaris, both clinically and histologically. The differential diagnosis is difficult and may depend on the detection of a few Leishmania amastigotes in the histologic sections, the growth of the promastigotes in cultures, or the identification of amastigotes by other techniques. Polymerase chain reaction was used to detect Leishmania amastigote DNA in tissue samples obtained from 65 patients with chronic lupoid leismaniasis, and the results were confirmed by Southern blot analysis.nnnOBSERVATIONSnThe histologic findings of a predominantly epithelioid cell granuloma surrounded by lymphocytic infiltrate in chronic lupoid leishmaniasis are very similar to those observed in lupus vulgaris. Extensive histologic examination of the sections in this series revealed occasional macrophages containing a few amastigotes in only 12 cases. Cultures in NNN medium yielded Leishmania promastigotes in 20 cases. Polymerase chain reaction studies using a Leishmania-specific primer identified Leishmania DNA in 30 of 63 cases, and those using a Mycobacterium tuberculosis primer were found to be negative for mycobacteria in 47 cases tested, including 11 cases with a positive tuberculin skin reaction.nnnCONCLUSIONSnThe histologic findings in chronic lupoid leishmaniasis resemble those of lupus vulgaris. Polymerase chain reaction studies were useful in identifying amastigotes in 30 (47.6%) of 63 cases. This study confirms the presence of DNA molecules of Leishmania amastigotes in samples of formalin-fixed, paraffin-embedded granulomatous tissue obtained from patients with chronic lupoid leishmaniasis.

Nevus Lipomatosus Cutaneus Superficialis (Hoffmann‐Zurhelle)

We are reporting seven cases with nevus lipomatosus cutaneus superficialis. A review of the literature indicates that this is a relatively rare type of connective tissue nevus with little more than 50 cases recorded. Localization of the cutaneous nodular lesions over the upper thigh and buttock and histologic findings of fat lobules within the substance of the nevoid malformation differentiate these lesions from other varieties of the connective tissue nevi.

Tumor of Follicular Infundibulum

A clinico-pathologic study is made of 12 cases with tumor of follicular infundibulum. This tumor appears as a slightly elevated keratotic lesion and is characterized histologically by proliferation of follicular sheath epithelium in the form of a thin subepidermal plate.

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.

Porokeratotic eccrine duct and hair follicle nevus

A 30-year-old patient had a linear lesion involving the forearm and hand for 30 years. Histologic examination of this lesion revealed hyperkeratosis, hypergranulosis, and acanthosis. There also were funnel-shaped areas of epidermal depression containing parakeratotic columns which penetrated hair follicles and sweat ducts. The differential diagnosis of this lesion is discussed.

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.

Pigmented basal cell carcinoma and superficial spreading malignant melanoma: an unusual combination*

We report pigmented lesions in 2 white male patients, which were clinically diagnosed as superficial spreading malignant melanoma and histologically showed combined features of superficial spreading malignant melanoma in situ and pigmented basal cell carcinoma. The significance of this association is not known but is most likely very rare.