The Many Faces of Seborrheic Keratoses T H O M A S R. W A D E , M.D. A N D A. B E R N A R D A C K E R M A N , M.D.
e b o r r h e i c k e r a t o s e s are benign skin lesions th a t o c c u r predom inantly in middle-aged and old e r persons. Ju s t as these c u ta n e o u s lesions m ay a p p e a r in a variety o f clinical a p p e a ra n c es, so to o , m ay th e y show wide variation in histologic findings. T he few est crite ria for histologic diagnosis o f a seborrheic kera to sis are (I) a lesion th a t is ex o p h y tic and endophytic and o f variable size, (2) benign e p ith e lial hyperplasia o f eith e r basaloid cells, squam o id cells o r both, and (3) delicately lam inated, amphophilically stained cornified ceils m assed a b o v e th e general su r face o f the epiderm is and within lesions as epithelial invaginations called pse u d o -c y sts o f horn. T w o o th e r histologic findings o f lesser im portance a re pig m enta tion by melanin and a b se n c e o f hypergranu lo sis. At p re se n t, s e b o rrh e ic ke ra to se s are divided into th re e histologic p a tte rn s, nam ely, (1) the acan th otic or solid type, (2) the reticulated o r adenoid type, and (3) the hyp e rk e ra to tic or papillom atous type. Although th e se histologic pa tte rn s are justifiable be c a u se they are com m only seen, w e believe th a t the classification is to o restrictive and not inclusive o f o th e r distinct his tologic variants o f s e b o rrh e ic k e ratoses. We present herew ith an atlas o f o u r e x p erien ce with various histologic p a tte rn s o f se b o rrh e ic k e ra to se s.
S
0 -° ^ >
Herbert Laboratories
Dermatology Division of Allergan Pharmaceuticals, Inc.
Irvine, California 92713, U.S.A. © 1979 H erb ert Laboratories
F ro m th e D e p a rtm e n ts o f D e rm a to lo g y a n d P ath o lo g y , N e w York U n iv e rsity M edical C e n te r, N e w Y ork, N e w Y ork.
WADE AN D A C K E R M A N
FIGURE 1A. The acantholic type o f seborrheic keratosis. The lesion is dome-shaped, smooth o f sur face, and has predominant basal-cell hyperplasia and pseudo-cysts o f horn, characteristics that are typical o f this common histologic pattern o f seborrheic keratoses. (H & E, 4 x)
FIGURE IB. A higher-power view o f Fig. IA shows the basal-cell hyperplasia and a pseudo-cyst o f horn containing delicate, laminated horn. (H & E, 40 x) ~ T
4
FIGURE 2A. The reticulated type o f seborrheic keratosis. The lesion has thin tracts o f pigmented basaloid cells that inter weave and surround pseudo-cysts o f horn, a characteristic o f this common histologic pattern o f seborrheic keratoses. This lesion on sun-damaged skin always begins as a solar lentigo that in time becomes hyperplastic and reticulated.
FIGURE 3. The digitate type o f seborrheic keratosis. The lesion is exo-endophytic and has characteristically delicate lamina tion o f the cornified layer and pseudo-cysts o f horn, features that are typical o f this histologic pattern o f seborrheic keratoses. (// & E, 4 x )
FIGURE 4. The pedunculated or sessile type o f seborrheic keratosis. The architecture o f this lesion in its prominent basal-cell hyperplasia and pseudo-cysts o f horn is characteris tic o f the pedunculated or sessile type o f seborrheic keratoses. (// & E, 4 x )
J. Dermatol. Surg. Oncol. 5:5 May 1979
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T H E M A NY FACES O F S E B O R R H E IC KERATOSES
FIGURE 5. The seborrheic keratosis with prominent pseudo-cysts o f horn. This lesion is differentiable from milia (small pseudo-cysts o f horn) by the interweaving tracts o f pigmented basaloid cells. In this type o f sebor rheic keratosis, the pseudo-cysts o f horn dominate the histologic pattern. (H & E, IOx.)
FIGURE 6. The papillated type o f seborrheic keratosis. This entirely exophytic lesion shows a predominantly papillated pattern, which makes it distinctively different from the smooth-surfaced and digitated forms o f seborrheic keratoses. (// & E, 4 x)
FIGURE 9A. A seborrheic keratosis with a nesting pattern. Sometimes in a seborrheic keratosis, basaloid cells containing pigment form in nests that are surrounded by squamoid cells. We prefer to term this the nesting pattern rather than the Borst-Jadassohn phenomenon. (H & E, lOx) FIGURE 9B. A higher magnification o f Fig. 9A shows the nesting pattern to better advantage. (H & E, 40x )
FIGURE 12B. A higher power view o f Fig. 12A show ing the deposits o f amyloid within the papillary dermis. (H & E, lOOx) FIGURE 12A. A seborrheic keratosis with deposition o f amyloid. This seborrheic keratosis shows amyloid within the thickened papillary dermis. Sometimes seborrheic keratoses have deposits o f amyloid within them, as do a variety o f both typical and atypical keratinocytic proliferations. {H & E. 16 x )
380
J . Dermatol. Surg. Oncol. 5:5 May 1979
WADE AN D A CK ERM AN
FIGURE 7. An early seborrheic keratosis. In this early lesion, one sees the beginnings o f baso-squamous acanthosis, papil lomatosis, hyperkeratosis, and formation o f pseudo-cysts o f horn. (H & E, 16 x )
FIGURE 8. Laminated cellular cornification in a seborrheic keratosis. This pattern o f hyperkeratosis is almost always diagnostic o f seborrheic keratoses. Similar cellular cornifica tion may be seen in some papillated epidermal nevi. The wavy pattern differentiates this form o f cellular cornification from that o f an infundibular cyst. (H & E, 16 x )
FIGURE 10. A pigmented seborrheic keratosis on sundamaged skin. The grey-blue elastotic material within the der mis is proof o f sun-damaged skin. A variety o f keratoses, not only solar keratoses, may occur on a background o f sundamaged skin. (H & E, 10x)
FIGURE 11. A reticulated type o f seborrheic keratosis and a solar lentigo. On the right side o f this photomicrograph o f a lesion in sun-damaged skin (note the solar elastosis within it) there is a solar lentigo and contiguous with it on the left there is a reticulated seborrheic keratosis. We believe both to be part o f a spectrum o f a single pathologic process. (H & E, 16 x )
FIGURE 13A. An inflamed seborrheic keratosis. In sebor rheic keratoses associated with dense inflammatory-cell infil trations, basaloid cells are converted into squamoid cells, probably by acceleration o f cellular maturation and increased epidermopoesis. (H & E, 4 x )
FIGURE 13B. A higher magnifica tion o f Fig. 13A shows the predom inant squamoidcell pattern found in inflamed sebor rheic keratoses. (H & E. 4 0 x)
T H E MA NY FA CES O F SE B O R R H E IC KERATOSES
FIGURE 14A. An irritated seborrheic keratosis. On either side o f this encrusted keratosis there are features o f a typical seborrheic keratosis. Some would term this baso-squamous papilloma with its eddies o f squamous cells an inverted follicu lar keratosis. We interpret it to be a portion o f a seborrheic keratosis that has been irritated. (H & E, 4 x )
FIGURE I4B. A higher-power view o f Fig. I4A shows the pseudo-cysts o f horn and eddies o f squamous cells in the center o f this irritated seborrheic keratosis. (H & E, 40 x )
FIGURE 16A. A seborrheic keratosis with squamous-cell car cinoma in situ. The pattern o f this lesion is clearly that o f a seborrheic keratosis, namely, papillated epithelial hyperplasia with pseudo-cysts o f horn. Strikingly atypical cells with large, equally atypical nuclei and prominent nucleoli are present foe ally within the hyperplastic epithelium. The latter findings are features o f squamous-cell carcinoma in situ (Bowen’s dis ease). (H & E, 4 x )
FIGURE 15A. An irritated seborrheic keratosis. Some sebor rheic keratoses that have been incompletely removed by shave biopsy may be misinterpreted as squamous-cell carcinomas. The clue to the correct diagnosis o f seborrheic keratosis for this crusted lesion with its eddies o f squamous cells is the presence o f pseudo-cysts o f horn containing delicately lami nated cornified cells. Eddies o f squamous cells are usually a sign o f a benign process. (// & E, 4 x )
FIGURE 15B. A higher magnifica tion o f Fig. I5A shows better the pseudo-cysts o f horn and eddies o f squamous cells. (H
e b o r r h e i c k e r a t o s e s are benign skin lesions th a t o c c u r predom inantly in middle-aged and old e r persons. Ju s t as these c u ta n e o u s lesions m ay a p p e a r in a variety o f clinical a p p e a ra n c es, so to o , m ay th e y show wide variation in histologic findings. T he few est crite ria for histologic diagnosis o f a seborrheic kera to sis are (I) a lesion th a t is ex o p h y tic and endophytic and o f variable size, (2) benign e p ith e lial hyperplasia o f eith e r basaloid cells, squam o id cells o r both, and (3) delicately lam inated, amphophilically stained cornified ceils m assed a b o v e th e general su r face o f the epiderm is and within lesions as epithelial invaginations called pse u d o -c y sts o f horn. T w o o th e r histologic findings o f lesser im portance a re pig m enta tion by melanin and a b se n c e o f hypergranu lo sis. At p re se n t, s e b o rrh e ic ke ra to se s are divided into th re e histologic p a tte rn s, nam ely, (1) the acan th otic or solid type, (2) the reticulated o r adenoid type, and (3) the hyp e rk e ra to tic or papillom atous type. Although th e se histologic pa tte rn s are justifiable be c a u se they are com m only seen, w e believe th a t the classification is to o restrictive and not inclusive o f o th e r distinct his tologic variants o f s e b o rrh e ic k e ratoses. We present herew ith an atlas o f o u r e x p erien ce with various histologic p a tte rn s o f se b o rrh e ic k e ra to se s.
S
0 -° ^ >
Herbert Laboratories
Dermatology Division of Allergan Pharmaceuticals, Inc.
Irvine, California 92713, U.S.A. © 1979 H erb ert Laboratories
F ro m th e D e p a rtm e n ts o f D e rm a to lo g y a n d P ath o lo g y , N e w York U n iv e rsity M edical C e n te r, N e w Y ork, N e w Y ork.
WADE AN D A C K E R M A N
FIGURE 1A. The acantholic type o f seborrheic keratosis. The lesion is dome-shaped, smooth o f sur face, and has predominant basal-cell hyperplasia and pseudo-cysts o f horn, characteristics that are typical o f this common histologic pattern o f seborrheic keratoses. (H & E, 4 x)
FIGURE IB. A higher-power view o f Fig. IA shows the basal-cell hyperplasia and a pseudo-cyst o f horn containing delicate, laminated horn. (H & E, 40 x) ~ T
4
FIGURE 2A. The reticulated type o f seborrheic keratosis. The lesion has thin tracts o f pigmented basaloid cells that inter weave and surround pseudo-cysts o f horn, a characteristic o f this common histologic pattern o f seborrheic keratoses. This lesion on sun-damaged skin always begins as a solar lentigo that in time becomes hyperplastic and reticulated.
FIGURE 3. The digitate type o f seborrheic keratosis. The lesion is exo-endophytic and has characteristically delicate lamina tion o f the cornified layer and pseudo-cysts o f horn, features that are typical o f this histologic pattern o f seborrheic keratoses. (// & E, 4 x )
FIGURE 4. The pedunculated or sessile type o f seborrheic keratosis. The architecture o f this lesion in its prominent basal-cell hyperplasia and pseudo-cysts o f horn is characteris tic o f the pedunculated or sessile type o f seborrheic keratoses. (// & E, 4 x )
J. Dermatol. Surg. Oncol. 5:5 May 1979
379
T H E M A NY FACES O F S E B O R R H E IC KERATOSES
FIGURE 5. The seborrheic keratosis with prominent pseudo-cysts o f horn. This lesion is differentiable from milia (small pseudo-cysts o f horn) by the interweaving tracts o f pigmented basaloid cells. In this type o f sebor rheic keratosis, the pseudo-cysts o f horn dominate the histologic pattern. (H & E, IOx.)
FIGURE 6. The papillated type o f seborrheic keratosis. This entirely exophytic lesion shows a predominantly papillated pattern, which makes it distinctively different from the smooth-surfaced and digitated forms o f seborrheic keratoses. (// & E, 4 x)
FIGURE 9A. A seborrheic keratosis with a nesting pattern. Sometimes in a seborrheic keratosis, basaloid cells containing pigment form in nests that are surrounded by squamoid cells. We prefer to term this the nesting pattern rather than the Borst-Jadassohn phenomenon. (H & E, lOx) FIGURE 9B. A higher magnification o f Fig. 9A shows the nesting pattern to better advantage. (H & E, 40x )
FIGURE 12B. A higher power view o f Fig. 12A show ing the deposits o f amyloid within the papillary dermis. (H & E, lOOx) FIGURE 12A. A seborrheic keratosis with deposition o f amyloid. This seborrheic keratosis shows amyloid within the thickened papillary dermis. Sometimes seborrheic keratoses have deposits o f amyloid within them, as do a variety o f both typical and atypical keratinocytic proliferations. {H & E. 16 x )
380
J . Dermatol. Surg. Oncol. 5:5 May 1979
WADE AN D A CK ERM AN
FIGURE 7. An early seborrheic keratosis. In this early lesion, one sees the beginnings o f baso-squamous acanthosis, papil lomatosis, hyperkeratosis, and formation o f pseudo-cysts o f horn. (H & E, 16 x )
FIGURE 8. Laminated cellular cornification in a seborrheic keratosis. This pattern o f hyperkeratosis is almost always diagnostic o f seborrheic keratoses. Similar cellular cornifica tion may be seen in some papillated epidermal nevi. The wavy pattern differentiates this form o f cellular cornification from that o f an infundibular cyst. (H & E, 16 x )
FIGURE 10. A pigmented seborrheic keratosis on sundamaged skin. The grey-blue elastotic material within the der mis is proof o f sun-damaged skin. A variety o f keratoses, not only solar keratoses, may occur on a background o f sundamaged skin. (H & E, 10x)
FIGURE 11. A reticulated type o f seborrheic keratosis and a solar lentigo. On the right side o f this photomicrograph o f a lesion in sun-damaged skin (note the solar elastosis within it) there is a solar lentigo and contiguous with it on the left there is a reticulated seborrheic keratosis. We believe both to be part o f a spectrum o f a single pathologic process. (H & E, 16 x )
FIGURE 13A. An inflamed seborrheic keratosis. In sebor rheic keratoses associated with dense inflammatory-cell infil trations, basaloid cells are converted into squamoid cells, probably by acceleration o f cellular maturation and increased epidermopoesis. (H & E, 4 x )
FIGURE 13B. A higher magnifica tion o f Fig. 13A shows the predom inant squamoidcell pattern found in inflamed sebor rheic keratoses. (H & E. 4 0 x)
T H E MA NY FA CES O F SE B O R R H E IC KERATOSES
FIGURE 14A. An irritated seborrheic keratosis. On either side o f this encrusted keratosis there are features o f a typical seborrheic keratosis. Some would term this baso-squamous papilloma with its eddies o f squamous cells an inverted follicu lar keratosis. We interpret it to be a portion o f a seborrheic keratosis that has been irritated. (H & E, 4 x )
FIGURE I4B. A higher-power view o f Fig. I4A shows the pseudo-cysts o f horn and eddies o f squamous cells in the center o f this irritated seborrheic keratosis. (H & E, 40 x )
FIGURE 16A. A seborrheic keratosis with squamous-cell car cinoma in situ. The pattern o f this lesion is clearly that o f a seborrheic keratosis, namely, papillated epithelial hyperplasia with pseudo-cysts o f horn. Strikingly atypical cells with large, equally atypical nuclei and prominent nucleoli are present foe ally within the hyperplastic epithelium. The latter findings are features o f squamous-cell carcinoma in situ (Bowen’s dis ease). (H & E, 4 x )
FIGURE 15A. An irritated seborrheic keratosis. Some sebor rheic keratoses that have been incompletely removed by shave biopsy may be misinterpreted as squamous-cell carcinomas. The clue to the correct diagnosis o f seborrheic keratosis for this crusted lesion with its eddies o f squamous cells is the presence o f pseudo-cysts o f horn containing delicately lami nated cornified cells. Eddies o f squamous cells are usually a sign o f a benign process. (// & E, 4 x )
FIGURE 15B. A higher magnifica tion o f Fig. I5A shows better the pseudo-cysts o f horn and eddies o f squamous cells. (H
