Homayoon Rahbari, M.D. and Amir H. Mehregan, M.D.

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.

Key Words: adnexal carcinoma-pilary complex; atypical basal cell epithelioma; adnexal differentiation; trichilemmal keratinization

JDA 1993;20:630-7

M. Mahroughan, M.D., Amir H. Mehregan, M.D., and David A. Mehregan, M.D.

Pinkus Dermatopathology Laboratory, Monroe, Michigan

Phakomatosis pigmentovascularis is a rare cutaneous malformation characterized by a combination of melanocytic nevi and nevus flammeus. We report a 16-year-old boy with extensive and predominantly unilateral skin involvement combining features of speckled melanocytic nevi over a background of nevus flammeus. A brief review of the literature and classification of this phakomatosis is presented.

David A. Mehregan, MD, Monroe, Michigan
Michael T. Bergeon, MD, Saginaw, Michigan
Darius R. Mehregan, MD, Monroe, Michigan

Epidermotropic metastatic malignant melanoma can simulate a primary malignant melanoma. However, since therapeutic management can be drastically different for these two lesions, care must be taken in evaluating them. We report a woman with forty-eight metastatic lesions of maligant melanoma, twenty-two of which were removed and found on histologic examination to be epidermotropic metastatic malignant melanoma.

CUTIS 1995; 55; 225-7

Melanie K. Kuechle, MD, Darius R. Mehregan, MD, Randall K. Roenigk, MD, and Sigfrid A. Muller, MD

Patients with atopic dermatitis have an increased susceptibility to certain viral infections, particularly those caused by Herpes simplex virus, human papilloma virus, and molluscum contagiosum. We describe two patients with atopic dermatitis who had unusually widespread and large lesions of molluscum contagiosum. One patient had a clonal proliferation of a T-cell population with an aberrant phenotype, and the other had persistent eosinophilia with marked elevation of IgE. The unusual clinical presentations of molluscum contagiosum and its association with altered immunity and atopic dermatitis are discussed.

Key words: atopic dermatitis, clonal T-cells, eosinophilia, increased IgE, molluscum contagiosum.

Eur J Dermatol 1996; 6: 274-7

David A. Mehregan, MD, Paul Vandersteen, MD, Lynn Sikorski, DO, and Darius R. Mehregan, MD, Monroe, Michigan

We report two cases of axillary granular parakeratosis which is a unique eruption involving the axilla that has distinctive histopathologic features. Both of our patients had slightly pruritic, hyperpigmented patches in the axilla. The biopsy specimens revealed severe compact parakeratosis with maintenance of the stratum granulosum and retention of keratohyalin granules throughout the stratum corneum which was markedly thickened and measured between 90 to 185 um. The exact etiology is not known, but this condition is believed to represent a contact reaction to an antiperspirant or deodorant.

JAAD 1995; 33; 373-5

Darius R. Mehregan, MD, David A. Mehregan, MD, Amir H. Mehregan, MD, Michael A Dorman, MD, and Edwin Cohen, MD

BACKGROUND: Spindle cell lipoma is an unusual and histologically distinctive form of lipoma occurring primarily in older individuals.

OBJECTIVE: The dermatologic surgeon and pathologist should be familiar with this variant of lipoma. METHODS: We are reporting two cases of spindle cell lipomas with the results of histologic examination with special stains and immunohistochemical studies.

RESULTS: The neoplasms consisted of lobulated masses of mature adipose tissue with areas of spindle cell proliferation. There was strong positive staining with antibodies for vimentin within the areas of spindle cell proliferation. One of the cases is unusual in that multiple lesions are occurring in a young patient.

CONCLUSION: Recognition of the histologic pattern is important in distinguishing the benign spindle cell lipoma from the malignant liposarcoma.

Dermatol Surg 1995; 21: 796-8

Ali Z. Momeni, MD, Shinichi Yotsumoto, MD, Darius R. Mehregan, MD, Amir H. Mehregan, MD, David A. Mehregan, MD, Mali Aminjavaheri, MD, Hiroshi Fujiwara, MD, and Joji Tada, MD

BACKGROUND: The 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 leishmaniasis, and the results were confirmed by Southern blot analysis.

Observations: The 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.

Conclusions: The 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.

Arch Dermatol 1996;132:198-202

Annette M. Dinneen, MBBCh, and Darius Mehregan, MD, Rochester, Minnesota

Background: Sebaceous epithelioma is a benign tumor that must be differentiated from basal cell carcinoma and other appendageal tumors.

Objective: Histologic and clinical findings were reviewed in 21 patients with sebaceous epitheliomas.

Methods: Twenty-one cases of sebaceous epithelioma collected during a 5-year period were reviewed.

Results: The tumors appeared as yellow to flesh-colored papules, most often on the face and neck. They consisted of basaloid cells with foci of sebaceous differentiation. Cystic spaces formed by holocrine degeneration or simulating sebaceous duct lining were common findings. Patients with sebaceous epitheliomas were more likely than the general population to have an internal malignancy.

Conclusions: Patients with sebaceous epithelioma should be examined for an underlying malignancy.

JAAD 1996;334:47-50

Homayoon Rahbari, M.D., Hossein Nabai, M.D., Amir H. Mehregan, M.D., David A. Mehregan, M.D., Darius R. Merhregan, M.D., and Judith Lipinski, M.D.

Background: The clinical appearance of amelanotic lentigo maligna melanoma (ALMM) is quite confusing and usually is not diagnosed prior to histopathologic examination.

Methods: We have studied four new patients with ALMM whose correct diagnosis was not obtained from any one clinical finding. We arrived at the final diagnosis in an unexpected way, having had biopsied the lesions for diagnoses other than malignant melanoma.

Results: ALMM presents as a nonspecific skin lesion with no single indicative characteristic. A search of the literature confirmed our difficulty in making the diagnosis.

Conclusions: To diagnose ALMM, one has to be cognizant of this condition and has to consider a constellation of findings that are unusual with melanocytic lesions. Questionable lesions must be biopsied for definitive histopathologic diagnosis.

KEYWORDS: amelanotic melanoma, lentigo maligna, dermatitic lesions, scaly elevated pruritus.

Cancer 1996; 77:2052-7

Darius R. Mehregan, MD, David A. Mehregan, MD and Amir H. Mehregan, MD, Monroe, Michigan

Abstract

Deep-penetrating nevus is a term proposed by Seab et al. to describe a distinctive benign melanocytic growth. The histologic differential diagnosis includes Spitz nevus, blue nevus, combined blue nevus and acquired melanocytic nevus, and malignant melanoma.

Clinically, the lesions often appear darkly pigmented. Clinicians may suspect either a blue nevus or a malignant melanoma and are often concerned about the extension of pigment into the subcutaneous fat at the time of excision.

Proliferating cell nuclear antigen (PCNA, cyclin) is a 36 kd marker of cellular proliferation that represents an accessory protein of DNA Delta-polymerase. The expression of PCNA is increased during the late G growth phase and peaks in the S phase of the cellular cycle. Recent studies have suggested that such markers of cellular proliferation may be useful in differentiating benign from malignant neoplasms or as prognostic markers in malignant neoplasms. Staining for PCNA has been reported in studies of squamous cell carcinoma, basal cell carcinoma, keratoacanthoma, and malignant melanoma. We have reviewed histologic sections of deep-penetrating nevi for the presence of PCNA and our results are reported.

JAAD 1995;33:685-7

Darius R. Mehregan, M.D., Amir H. Mehregan, M.D., and David A. Mehregan, M.D., Monroe, Michigan

Malakoplakia is an uncommon granulomatous infectious disease that is found primarily in the genito-urinary tract, but may rarely involve the skin. Histologic findings are marked by the presence of foamy macrophages containing basophilic concentric spherules, the Michaelis-Gutman bodies. Micro-organisms are not readily identifiable. Immunostaining with polyclonal anti-mycobacterium bovis (BCG) has been described as a method of identifying bacterial and fungal organisms in situations where organisms may be sparse. We report two cases of cutaneous malakoplakia with demonstration of organisms by immunostaining with anti-BCG antibodies.

JAAD; 43:351-4

Darius R. Mehregan, M.D., Amir H. Mehregan, M.D., and David A. Mehregan, M.D., Monroe, Michigan

We stained benign melanocytic nevi and malignant melanoma with antibodies to melanoma antigen recognized by T cells (Mart-1) to determine if this was useful in differentiating benign from malignant melanocytic neoplasms. Forty-five primary malignant melanomas and 71 benign melanocytic nevi were stained with antibodies to Mart-1. Two cases of malignant melanoma metastatic to lymph node and three cutaneous metastases of malignant melanoma were also stained. The degree of staining was graded into diffuse positive staining, focal positive staining, and negative staining. Thirty-six of 45 primary malignant melanomas stained diffusely positive with antibodies to Mart-1. This included three of five desmoplastic malignant melanomas that showed positive staining. Four melanomas showed faint or focal positive staining. One of two metastases to lymph node showed strong positive staining and one showed no staining. All three cutaneous metastases showed diffuse positive staining. Sixty-one of 71 melanocytic nevi showed no staining or faint staining with antibodies to Mart-1. Ten of 71 melanocytic nevi showed strong positive staining. The majority of these were congenital nevi. Staining with antibodies to Mart-1 antigen was a useful marker of malignant melanoma. However, staining may also be seen in benign melanocytic neoplasms. The presence or absence of staining for Mart-1 antigen cannot be used to differentiate benign melanocytic nevi from malignant melanocytic tumors.

Key Words: Immunohistochemistry; Mart-1; Melanoma; Melanoma antigen related to T cells; Nevus; Pathology; Spitz Nevus

Am J Dermatopathol 2000; 22: 247-250