Clinical and Experimental Dermatology (i979) 4) 59-
Trichilemmomal horn: cutaneous horn overlying trlchilemmoma
M.H.BROWNSTEIN AND E.E.SHAPIRO Laboratory of Dermatopathology, Great Neck, N. Y., and the Departments of Dermatology and Pathology, Nezv York Medical College-Metropolitan Hospital Center, Nezv York, N.Y., U.S.A. Accepted for publication i% May 1978
Summary Four patients had keratotic, horn-shaped growths on the face or scalp. Histologically, each showed massive, largely orthokeratotic horn with a trichilemmoma at the base. Trichilemmomal horn (cutaneous horn overlying trichilemmoma) must be differentiated from trichilemmal horn, a cutaneous horn that shows trichilemmal rather than epidermoid keratinization.
Recent interest in trichilemmoma has centred on recognition that solitary tumors are relatively common (Brownstein & Shapiro, i973)> and that multiple facial trichilemmomas are specifically associated with Cowden's syndrome (Brownstein, Mehregan & Bikowski, 1977), and an increased incidence of breast cancer in women (Brownstein, Wolf & Bikowski, 1978). Our purpose here is to describe trichilemmomal horn (trichilemmoma at the base ofa cutaneous horn) and to differentiate it from trichilemmal horn (cutaneous horn showing trichilemmal keratinization).
Case Summaries Case I. A 55-year-old man had a hard, horn-shaped, asymptomatic growth on his right upper cheek for 8 months (Fig. i). It measured 2 mm at the base and 8 mm high. Microscopic examination (Figs 2 and 3) showed a massive protrusion of horn that was largely orthokeratotic. An acaniJiotic lobular mass extended into the corium and included many paleReprint requests: Dr Brownstein, Laboratory of Dermatopathology, P.O. Box 400, Great Neck, N.Y. 11022, U.S.A. 0307-6938/79/0300-0059502.00
(0 1979 Blackwell Scientific Publications
59
6o
M.H.Brownstein and E.F.Shapiro
Figure i, Trichilemmomal horn on right upper cheek. Case i.
staining tumour cells that contained large amounts of PAS-positive, diastase-labile material. Cells in the basal layer showed a tendency to palisading and rested on a thick basement membrane. The histologic diagnosis was cutaneous horn overlying a trichilemmoma. Case 2. A 63-year-old man had an elevated, keratotic growth on his chin for a few months. The clinical impression was cutaneous horn overlying an actinic keratosis. Histologic examination showed a cutaneous horn with a trichilemmoma at its base (Figs 4 and 5). Case 3. An 80-year-old man had a i year history ofa raised, keratotic, 8 x 5 mm lesion on his scalp. Histologic examination showed a cutaneous horn overlying a trichilemmoma. Case 4. A 77-year-old woman had a cutaneous horn of unknown duration on her right temple. Microscopic examination disclosed a trichilemmoma at the base ofa cutaneous horn. Comment
•-;'
v
Cutaneous horn is not a complete diagnosis, but a reaction pattern of exaggerated hyperkeratosis. ClinicaUy, the growth is typically conical, very hard, and resembles an animal's horn in miniature. The important issue is not the horn itself, which is dead keratin, but rather the nature of the condition at the base, which may be premalignant (solar keratosis, arsenical keratosis, Bowen's disease), benign (seborrhoeic keratosis, viral wart, histiocytoma, inverted follicular keratosis, verrucous epidermal naevus, organoid naevus, angioma), or malignant (squamous cell carcinoma, rarely basal cell carcinoma, Kaposi's sarcoma, or sebaceous carcinoma). Trichilemmoma, a benign glycogen-rich clear cell follicular tumour, is related to the lower nonkeratinizing portion of the trichilemma (outer root sheath). Paradoxically, trichilemmoma does not show the trichUemmal type of keratinization seen in trichilemmal cyst and
Trichilemmomal horn
6i
Figure 2. Trichilemmomal horn showing massive protrusion of keratin. Case i (H & E, x 50).
related lesions. Rather, at the surface, trichilemmomas display epidermoid keratinization which is frequently pronounced, with a thick granular layer and outstanding hyperkeratosis. Since conditions such as seborrhoeic keratosis, viral wart, solar keratosis, arsenical keratosis, and Bowen's disease, may form cutaneous horns, it is not surprising that trichilemmoma, a tumour that also shows a tendency to surface hyperkeratosis, is also capable of generating a cutaneous horn. An important consideration is to differentiate trichilemmomal horn (cutaneous horn overlying trichilemmoma) from trichilemmal horn (cutaneous horn showing trichilemmal keratinization). The problem is largely one of terminology, since keratinization in trichilemmomal horn is epidermoid and in trichilemmal horn is trichilemmal. We have studied eighteen trichilemmal horns during the past 5 years and are reporting our findings elsewhere. These usually occur on the back or limbs and show massive, largely
62
M.H.Brownstein and H.E.Shapiro
Figure 3. Trichilemmomal horn showing tumour at tbe base with lobular acanthosis, pale cells, and prominent palisading at the tower margin. Case i (H & E, x 200).
Figure 4. Trichilemmoma at base of cutaneous horn (trichilemmomal horn). Case 2 (H & B, x 50).
Trichilemmomal horn
63
F i g u r e 5. Base of trichilemmomal horn showing palisading of cells at lower margin and many pale cells. Case 2 (H & E, x 200).
orthokeratotic hyperkeratosis with trichilemmal keratinization at the base. In many instances it is possible to identify small trichilemmal cyst-like structures in the upper cutis that open directlv to the surface to form a cutaneous horn. Ackucwledgment We wish to thank Mr Fred Liebman for providing the photomicrographs. References BROWNSTEIN, M.H. & SHAPIRO, L . (1973) Trichilemmoma: analysis of 40 new cases. Archives of Dermatology, 107, 865. BROWNSTEIN, M.H., MEHREGAN, A.H. & BIKOWSKI, J.B. (1977) Trichilemmomas in Cowden's disease.
Journal of the American Medical Association, 238, 26. BROWNSTEIN, M.H., WOLF, M . & BIKOWSKI, J.B. (1978) Cowden's syndrome. A cutaneous marker of breast cancer. Cancer, 41, 2393.
Trichilemmomal horn: cutaneous horn overlying trlchilemmoma
M.H.BROWNSTEIN AND E.E.SHAPIRO Laboratory of Dermatopathology, Great Neck, N. Y., and the Departments of Dermatology and Pathology, Nezv York Medical College-Metropolitan Hospital Center, Nezv York, N.Y., U.S.A. Accepted for publication i% May 1978
Summary Four patients had keratotic, horn-shaped growths on the face or scalp. Histologically, each showed massive, largely orthokeratotic horn with a trichilemmoma at the base. Trichilemmomal horn (cutaneous horn overlying trichilemmoma) must be differentiated from trichilemmal horn, a cutaneous horn that shows trichilemmal rather than epidermoid keratinization.
Recent interest in trichilemmoma has centred on recognition that solitary tumors are relatively common (Brownstein & Shapiro, i973)> and that multiple facial trichilemmomas are specifically associated with Cowden's syndrome (Brownstein, Mehregan & Bikowski, 1977), and an increased incidence of breast cancer in women (Brownstein, Wolf & Bikowski, 1978). Our purpose here is to describe trichilemmomal horn (trichilemmoma at the base ofa cutaneous horn) and to differentiate it from trichilemmal horn (cutaneous horn showing trichilemmal keratinization).
Case Summaries Case I. A 55-year-old man had a hard, horn-shaped, asymptomatic growth on his right upper cheek for 8 months (Fig. i). It measured 2 mm at the base and 8 mm high. Microscopic examination (Figs 2 and 3) showed a massive protrusion of horn that was largely orthokeratotic. An acaniJiotic lobular mass extended into the corium and included many paleReprint requests: Dr Brownstein, Laboratory of Dermatopathology, P.O. Box 400, Great Neck, N.Y. 11022, U.S.A. 0307-6938/79/0300-0059502.00
(0 1979 Blackwell Scientific Publications
59
6o
M.H.Brownstein and E.F.Shapiro
Figure i, Trichilemmomal horn on right upper cheek. Case i.
staining tumour cells that contained large amounts of PAS-positive, diastase-labile material. Cells in the basal layer showed a tendency to palisading and rested on a thick basement membrane. The histologic diagnosis was cutaneous horn overlying a trichilemmoma. Case 2. A 63-year-old man had an elevated, keratotic growth on his chin for a few months. The clinical impression was cutaneous horn overlying an actinic keratosis. Histologic examination showed a cutaneous horn with a trichilemmoma at its base (Figs 4 and 5). Case 3. An 80-year-old man had a i year history ofa raised, keratotic, 8 x 5 mm lesion on his scalp. Histologic examination showed a cutaneous horn overlying a trichilemmoma. Case 4. A 77-year-old woman had a cutaneous horn of unknown duration on her right temple. Microscopic examination disclosed a trichilemmoma at the base ofa cutaneous horn. Comment
•-;'
v
Cutaneous horn is not a complete diagnosis, but a reaction pattern of exaggerated hyperkeratosis. ClinicaUy, the growth is typically conical, very hard, and resembles an animal's horn in miniature. The important issue is not the horn itself, which is dead keratin, but rather the nature of the condition at the base, which may be premalignant (solar keratosis, arsenical keratosis, Bowen's disease), benign (seborrhoeic keratosis, viral wart, histiocytoma, inverted follicular keratosis, verrucous epidermal naevus, organoid naevus, angioma), or malignant (squamous cell carcinoma, rarely basal cell carcinoma, Kaposi's sarcoma, or sebaceous carcinoma). Trichilemmoma, a benign glycogen-rich clear cell follicular tumour, is related to the lower nonkeratinizing portion of the trichilemma (outer root sheath). Paradoxically, trichilemmoma does not show the trichUemmal type of keratinization seen in trichilemmal cyst and
Trichilemmomal horn
6i
Figure 2. Trichilemmomal horn showing massive protrusion of keratin. Case i (H & E, x 50).
related lesions. Rather, at the surface, trichilemmomas display epidermoid keratinization which is frequently pronounced, with a thick granular layer and outstanding hyperkeratosis. Since conditions such as seborrhoeic keratosis, viral wart, solar keratosis, arsenical keratosis, and Bowen's disease, may form cutaneous horns, it is not surprising that trichilemmoma, a tumour that also shows a tendency to surface hyperkeratosis, is also capable of generating a cutaneous horn. An important consideration is to differentiate trichilemmomal horn (cutaneous horn overlying trichilemmoma) from trichilemmal horn (cutaneous horn showing trichilemmal keratinization). The problem is largely one of terminology, since keratinization in trichilemmomal horn is epidermoid and in trichilemmal horn is trichilemmal. We have studied eighteen trichilemmal horns during the past 5 years and are reporting our findings elsewhere. These usually occur on the back or limbs and show massive, largely
62
M.H.Brownstein and H.E.Shapiro
Figure 3. Trichilemmomal horn showing tumour at tbe base with lobular acanthosis, pale cells, and prominent palisading at the tower margin. Case i (H & E, x 200).
Figure 4. Trichilemmoma at base of cutaneous horn (trichilemmomal horn). Case 2 (H & B, x 50).
Trichilemmomal horn
63
F i g u r e 5. Base of trichilemmomal horn showing palisading of cells at lower margin and many pale cells. Case 2 (H & E, x 200).
orthokeratotic hyperkeratosis with trichilemmal keratinization at the base. In many instances it is possible to identify small trichilemmal cyst-like structures in the upper cutis that open directlv to the surface to form a cutaneous horn. Ackucwledgment We wish to thank Mr Fred Liebman for providing the photomicrographs. References BROWNSTEIN, M.H. & SHAPIRO, L . (1973) Trichilemmoma: analysis of 40 new cases. Archives of Dermatology, 107, 865. BROWNSTEIN, M.H., MEHREGAN, A.H. & BIKOWSKI, J.B. (1977) Trichilemmomas in Cowden's disease.
Journal of the American Medical Association, 238, 26. BROWNSTEIN, M.H., WOLF, M . & BIKOWSKI, J.B. (1978) Cowden's syndrome. A cutaneous marker of breast cancer. Cancer, 41, 2393.
