G r o s s a n d r n i c r o s c o o i c sVrnOosium Porokeratotic eccrine duct and hair follicle nevus Ralph J. C o s k e y , M . D . , Amir H. Mehregan, M . D . , and Ken H a s h i m o t o , M.D.
Detroit, All 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. (J AM ACAO DERMATOL 6:94-0-943, 1982.)
W e are presenting a c a s e of a patient w h o had a linear lesion i n v o l v i n g the left forearm and the hand. It was studded with plugs o f whitish-colored keratin and was clinically diagnosed as a nevus c o m e d o n i c u s . H o w e v e r , histologic examination o f a b i o p s y specimen s h o w e d changes more compatible with porokeratosis o f Mibelli.
CASE REPORT A 30-year:old man was seen because of an asymptomatic lesion involving the left forearm and left hand. It had been present since the age of 2. Other members of his family did not have a similar problem. Physical examination revealed a linear, erythematous, slightly scaIy plaque extending 15 cm down the ulnar aspect of the left forearm to the wrist. Once the lesion reached the wrist it changed in character. Here multiple dilated orifices measuring 1 to 2 cm in diameter appeared. Each dilated orifice was filled with whitish-colored keratin. Groups of these dilated papules extended onto the distal end of the palmar surface of the fourth finger and halfway onto the palmar surface of the third finger. The lesion again became erythematous and somewhat verrucous on the proximal aspect of the dorsum of the fourth and fifth fingers (Figs. 1 and 2). Histopathologie examination. Biopsies were obtained from the wrist, the palm, and the fingers. All From the Department of Dermatology, Wayne State University School of Medicine. Reprint requests to: Dr. Ralph J. Coskey, 23133 Orchard Lake Rd., Farmlngton, MI 48024.
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sections showed moderate thickening of the epidermis, with hypergranulosis and hyperkeratosis. In addition, biopsies taken from the wrist showed funnel-shaped areas of epidermal depression with loss of granular layer, giving rise to columnar masses of parakeratotic material resembling that of a cornoid lamella. Serial sections of biopsies taken from the wrist revealed occlusion of both the hair follicles and eccrine sweat ducts, with parakeratotic plugs (Figs. 3-6). Biopsies from the palm and finger revealed cornoid lamella-like structures occluding dilated eccrine sweat ducts with no significant histopathologic changes in the underlying dermis. DISCUSSION The following linear lesions were considered in the differential diagnosis of this patient's dermatosis: nevus comedonicus, linear verrucous epidermal nevus, inflammatory linear verrucous epidermal nevus, linear psoriasis, linear lichen planus, linear porokeratosis, " c o m e d o naevus of the p a l m - - a sweat duct n a e v u s , ' " and "porokeratotic eccrine ostial and dermal duct naevus. 2'' Nevus comedonicus is usually unilateral and often has a linear configuration, but at times it may be bilateral or may be randomly distributed. Five cases have been reported with palmoplantar involvement. 3-5 Lesions are characterized by closely set dilated orifices, filled with keratin-producing comedo-like structures. The histologic examination of a typical lesion is characterized by struc0t90-9622/82/050940+04500.4o/0 © 1982 Am Acad Dermatol
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Fig. 1. Linear, erythernatous, slightly scaly plaque extending distally on ulnar-volar surface of forearm to palm.
Fig. 2. Multiple pits filled with white keratin plugs. tures resembling dilated hair follicles containing orthokeratotic horny plugs. Nevus comedonicus is thought to be a developmental abnormality of the pilosebaceous apparatus. 5 Lesions on the palms and soles may be due
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Fig. 3. Biopsy from wrist showing hyperkeratosis, acanthosis, and funnel-shaped areas of epidermal depression, giving rise to columnar masses of parakeratotic material resembling cornoid lamellae. (Hematoxylin-eosin stain; original magnification, × 40.) to occlusion of eccrine glands that have undergone metaplastic keratinization or may be a heterologous hamartoma, while those on the hairy parts of the body may be a homologous hamartoma? Although our case resembles a nevus comedonicus clinically, the histologic findings of parakeratotic cornoid larnellae invaginating into sweat ducts and hair follicles would rule against this diagnosis. A linear verrucous epidermal nevus may be present at birth or appear during childhood or adolescence. It usually is a hyperkeratotic flesh- or brownish-colored lesion. Histologically one sees hyperkeratosis, acanthosis, papillomatosis, and elongation of the fete ridges. 6"7 Our patient had some features of this entity, but the presence of
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Fig. 4. Biopsy from the wrist showing a parakeratotic plug penetrating into a hair follicle. (Hematoxylineosin stain; original magnification, x 125.)
Fig. 5. Biopsy from wrist showing a parakeratotic plug penetrating into the sweat duct lumen. (Hematoxylineosin stain; original magnification, × 125.)
comedonal-iike papules on the palm would rule against this diagnosis. Inflammatory linear verrucous epidermal nevus is characterized by a scaling, red, dermatitic-like lesion present in a linear fashion. It is most commonly seen on the lower extremities and usually appears in childhood. 8 Histologically, one sees acanthosis with alternating areas of hyperkeratosis and parakeratosis, as well as a chronic inflammatory infiltrate in the dermis. This entity, along with linear psoriasis and linear lichen planus, does not present with comedo-like lesions and, except for being linear, does not resemble that of our patient. Linear porokeratosis, which is a variant of porokeratosis of Mibelli, often appears during childhood. It may be mistaken for linear verrucous epidermal nevus, lichen striatus, or lichen planus. Rahbari et aP described eight cases of it and found
seven other instances of it recorded in the literature. Close examination of these linear lesions usually will reveal the classic finding seen in porokeratosis, with confluent and discreet lesions containing an atrophic center, surrounded by a ridge with a thin furrow having keratotic material in it, corresponding to the cornoid lamella. The parakeratotic cornoid larneila in porokeratosis tends to involve both the eccrine sweat duct, infundibular portion of the hair follicle, and also the interfollicular epidermis. The involved epidermis may either be hyperplastic or atrophic. In our case we did not see the typical clinical findings of linear porokeratosis, and, although the histologic findings were somewhat similar to porokeratosis, they did not show cornoid lamellae in the interadnexal epidermis. Marsden et al ~ described the case of a 9-
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Fig. 6, Biopsy from wrist showing a parakeratotic plug over eccrine sweat duct. (Hematoxylin-eosin stain; original magnification, × 125.) year-old child with keratotic pits involving the left palm. The lesions had appeared at birth. Clinically they resembled a c o m e d o nevus. However, histologic examination showed dilated sweat ducts, many of which were filled with a parakeratotic filiform phlg. S o m e o f the plugs had slitlike cavities resembling sweat duct lumens. At the base of the plugs the granular layer was absent and the epidermal cells were vacuolated. The authors felt that their patient did not have porokeratosis. They labeled their case as a " c o m e d o naevus of the p a l m - - a sweat duct n a e v u s . " Abell and Read" described a similar case. They labeled their case " p o r o k e r a t o t i c eccrine ostial and dermal duct n a e v u s . " Their patient was a 3-year-old girl who had a linear keratotic lesion present since birth, consisting of tiny papules extending along the medial surface of the left foot from the great toe toward the ankle. Histologic examination of a specimen taken from the lesion showed changes similar to Marsden et al's case. Our patient had s o m e features of the latter two cases. H o w e v e r , in addition to sweat duct in-
volvement, he also had i n v o l v e m e n t o f hair follicles. Probably this case is a distinct entity. Perhaps it should be called a "porokeratotic eccrine duct and hair follicle n e v u s . " REFERENCES
I. Marsden RA, Fleming A, Dawber RPR: Comedo naevus of the palm--a sweat duct naevus. Br J Dermatol 101:717-722, 1979. 2. Abell E, Read SI: Porokeratotic eccrine ostial and dermal duct naevus. Br J Dermatol 103:435-441, i980. 3. Wood MG, Thew MA: Nevus comedonicus. A case with palmar involvement and review of the literature. Arch Dermatol 98:111-116, 1968. 4. Leppard B, Marks R: Comedone naevus. A report of nine eases. Trans St. Johns Hosp Dermatol Soc 59:45-51, 1973. 5. Beck MH, Dave VD: Extensive nevus comedonicus. Arch Dermatol 116:1048-1050, 1980. 6. Pinkus H, Mehregan AH: A guide to dermatohistopathology, ed. 3. New York, 1981, Appleton-Century-Crofts. 7. Lever WF, Schaumburg-Lever G: Histopathology of the skin, ed. 5. Philadelphia, 1975, J. B. Lippincott Co. 8. Altman J, Mehregan AH: Inflammatory linear verrucous epidermal nevus. Arch Dermatol 104:385-389, 1971. 9. Rahbari H, Cordero AA, Mehregan AH: Punctate porokeratosis. A clinical variant of porokeratosis of Mibelli. J Cutan Pathol 4:338-341, 1977.