Keratin Horn Research Articles

Palisaded Encapsulated (Solitary Circumscribed) Neuroma: A Review of 30 Cases.

Background. Solitary circumscribed neuroma (SCN), also known as palisaded encapsulated neuroma (PEN), is a benign neural tumor. It may be mistaken as either schwannoma or neurofibroma in pathology practice. In this study, we aimed to define clinicopathologic and immunohistochemical features and discuss its differential diagnosis. Materials and Methods. The histopathological features of 30 cases of SCN/PEN were reviewed. The presence of intralesional axons, Schwann, and perineural cell distributions were investigated by performing neuronal immunomarkers. Results. Twelve cases were females, and 18 cases were males. The mean age was 48 years. Lesions were mostly located on the face (27/30). Histologically, 18 had a lobular pattern, 9 were plexiform, 2 fungating, and 1 multilobular. Although the majority of cases were well circumscribed, capsular integrity was at least focally disrupted (73%). Verocay body was noted only in 6 cases (20%). One case showed excessive hyperkeratosis, forming a keratin horn. Adipocytic change was detected in another case. The lesions consisted of S100-positive Schwann cell proliferation and were partially surrounded by perineural cells highlighted by EMA or Claudin-1. The amount of intralesional axons revealed by neurofilament immunostaining was variable. Conclusion. SCN/PEN is a relatively common lesion, and usually seen as an asymptomatic papule on the face of elderly patients. A circumscribed lesion composed of bundles of bland-looking spindle cells thought to be of neural origin is seen in the dermis. Pathologists should be aware of the existence of plexiform and multilobular PEN/SCN variants, to avoid misdiagnosis of plexiform neurofibroma or schwannoma.

Retraction note: Cyto-histopathological and outcome features of the prepuce squamous cell carcinoma of a mixed breed dog.

Squamous cell carcinomas (SCCs) are uncommon, high-grade tumors, predominantly composed of round cells in the prepuce. The aim of this study is to better define the clinicopathologic features of this neoplasm. We conducted cyto-histopathologic analysis on the manifestations of the prepuce SCC by H & E staining in a terrier mix dog. Grossly, tumor was large, multiple erythematous patch, and ulcerated masses frequently affecting the prepuce and deeply invading to distal prepuce out from the ventro-lateral of penis and the tumor covered by a necrotic discharge. Cytological evaluation of fine-needle aspirates from the cutaneous mass from the prepuce comprised of round nuclei, coarse chromatin pattern, distinct nucleoli and nuclear pleomorphism. Furthermore, the neoplastic cells were pleomorphic, round to caudate in shape, exhibiting prominent anisokaryosis and anisocytosis with rare mitotic features. Microscopically, the lesions were predominantly composed of atypical round cells disposed in interlacing fascicles. Frequent findings include keratin formation, horn pearls, mitoses and cellular atypia. The cells showed distinct borders, ranged from polygonal to round or elongate and had moderate amounts of eosinophilic cytoplasm. The histopathologic features coupled with the cytopathology findings led to a diagnosis of squamous cell carcinoma. To the authors’ knowledge, this is the first time that multiple erythematous plaques have undergone malignant transformation in a terrier mix dog. The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/5748771971272873

Mechanical and Thermal Characterisation of Poly (Ethylene) and Thermoplastic Starch Filled with Keratin Horn Powder from Bovine Claws

Mechanical and Thermal Characterisation of Poly (Ethylene) and Thermoplastic Starch Filled with Keratin Horn Powder from Bovine Claws

Diagnostic Pitfalls of Differentiating Cellular Digital Fibroma from Superficial Acral Fibromyxoma.

Dear Editor: Acquired digital fibrokeratoma is an exophytic tumor with hyperkeratotic epidermis on acral sites. Meanwhile, cellular digital fibroma (CDF) is a unique subset of acquired digital fibrokeratomas that comprise slender spindle-shaped CD34-positive cells1. Here, we report a rare case of CDF and its clinicopathologic characteristics. A 38-year-old Korean man presented with a painless nodule, which began to grow six months prior to examination, on the ventral part of the proximal phalanx of his right index finger. Physical examination revealed a fixed erythematous protruding nodule 0.5 cm in diameter (Fig. 1A). The results of punch biopsy for complete removal showed a polypoid tumor constricted at its base and lateral sides by acanthotic epidermis with collarette-like changes (Fig. 1B). Collagenous bundles were filled mostly with myxoid materials and numerous spindle cells arranged in a loose fascicular pattern (Fig. 1C). No nuclear atypia or mitoses were identified. Immunohistochemistry revealed most proliferative spindle cells were positive for CD34 (Fig. 1D) and vimentin (Fig. 1E) but negative for CD99, S-100, and smooth muscle actin. Prominent myxoid stroma was detected by Alcian blue stain (Fig. 1F). On the basis of these findings, the lesion was diagnosed as CDF. After the lesion was completely removed, the patient did not experience any recurrence over 18 months of follow-up. Fig. 1 (A) An erythematous fixed protruding nodule 0.5 cm in diameter on the ventral part of the proximal phalanx of the patient's right index finger. (B~F) Low-magnification view of the specimen indicates a polypoid tumor protruding above the surrounding skin. ... Since McNiff et al.1 first described CDF in 2005, their observations have been regarded as important for the diagnosis of fibrohistiocytic neoplasms, which can be easily misdiagnosed as superficial acral fibromyxoma (SAFM)2. We initially considered a diagnosis of SAFM in our case; however, clinically, SAFMs are slow-growing asymptomatic tumors that commonly present as solitary lesions ranging from 0.5 to 5 cm in diameter3,4. The lesion in the present case was relatively smaller than typical SAFMs. Histopathologically, both SAFM and CDF can be characterized by spindle to stellate cells arranged in a storiform or fascicular pattern with variable degrees of myxoid background stroma5. Accentuated microvasculature and conspicuous mast cells are potentially suggestive of SAFM; meanwhile, keratin horn and epidermal collarette are commonly observed in CDF4,5. In our case, the nodule showed proliferation of spindle cells in a loose fascicular pattern; however, it was constricted at its base and lateral sides by collarette-like acanthotic epidermis. No vascular proliferation, atypical mitoses, or fibroblasts oriented vertically to the axis of the lesion were observed. In addition, the lesion was negative for CD99. Therefore, the tumor was consistent with a diagnosis of CDF. If lesions resemble myxoid fibrohistiocytic tumors (Table 1), immunohistochemistry can be used for an accurate diagnosis of CDF. Table 1 Characteristics of myxoid soft-tissue tumors mimicking cellular digital fibroma McNiff et al.1 report that the natural course of CDF appears to be benign owing it its small size, unremarkable cytology, and absence of recurrence after biopsy. However, elucidating the detailed pathophysiology and clinical characteristics of CDF requires additional case reports. Rare cases of CDF, such as the one presented herein, must be distinguished from other cutaneous fibrohistiocytic tumors including SAFM.

Clinico-pathological correlation of localised Dowling-Degos disease

A 26-years-old young man came with complaints of abnormally dark skin coloring (hyperpigmentation), particularly in the back of the hands and intertriginous folds between digits, progressively spreading since last 5 years without any family history of the same. He was diagnosed with clinical diagnosis of hyper-pigmented disorder under evaluation most probably medication induced. He had no personal and family history of such skin disease or diabetes mellitus. We received a skin biopsy of 0.3 × 0.3 cm which was totally embedded for histopathology reporting. Section studied through skin reveals epidermis, dermis and subcutaneous tissue. Epidermis shows hyperkeratosis, irregular acanthosis with focal filliform down growth of epidermis. Multiple keratin horn cysts were seen in the down growth. The tips of rete ridges showed pronounced hyperpigmentation. Histopathological impression was given as Dowling-Degos disease (DDD). DDD is a rare genetic skin condition without definite cure, although its prevalence is unknown. So we report a DDD case in a young man with clinico-pathological correlation.

Localized Dowling-Degos disease

A 26-year-old young man came with complaints of abnormally dark skin coloring, particularly in the back of the hands and intertriginous folds between digits, progressively spreading in the last 5 years. There was no family history of the same. He had no personal and family history of skin disease or diabetes mellitus. A clinical diagnosis of drug-induced hyperpigmentation disorder was made. A skin biopsy of 0.3 cm × 0.3 cm which was totally embedded for histopathology reporting was obtained. The section revealed epidermis, dermis, and subcutaneous tissue. Epidermis shows hyperkeratosis, irregular acanthosis with focal filliform down growth of the epidermis. Multiple keratin horn cysts were seen in the down growth. The tips of rete ridges showed pronounced hyperpigmentation. The histopathological impression was Dowling-Degos disease (DDD). DDD is a rare genetic skin condition without a definite cure, although its prevalence is unknown. We report a DDD case in a young man.

Corneal keratin horn in a case of ocular cicatricial pemphigoid: A relentless disease

We report a rare case of progressive corneal blindness in a 65-year-old female, who was diagnosed as cicatricial pemphigoid, after almost three decades of suffering recurrent oral ulcerations. The left eye was affected earlier, and to a greater extent and severity. Subsequently, the disease progressed to complete corneal keratinization in the left eye. This case highlights the natural course of the disease, wherein the patient finally sought ophthalmic consultation for the recurrent appearance of a horn like growth in the left eye along with vision impairment due to cataractous change in the less affected right eye. At this time, patient had obvious features of ocular cicatricial pemphigoid (OCP) such as formation of multiple symblephara in the right eye and a hard dry growth in an immobile, blind left eye. To the best of our knowledge, corneal keratin horn formation has not been reported as a feature of OCP so far.

Badehauben-großes mikrozystisches Adnexkarzinom in Kollision mit einem Bowenkarzinom nach photodynamischer Therapie

Microcystic adnexal carcinoma (MAC) is a rare, often over years slowly growing tumor of the sweat glands with an aggressive infiltrative growth. It is histologically characterized by superficial epithelial nests with central keratin horn cysts. In the deeper regions syringoid epithelial nests with perineural growth are typical for this tumor entity. We report on a 71-year-old male patient applied to our outpatient clinic with multiple carcinomata in situ on his head. Seven years ago he underwent a photodynamic therapy (PDT). Again we performed a PDT and excised a lesion on the occipital area of the head suspected as squamous cell carcinoma. After nine micrographically controlled excisions a defect resulted which involved the complete scalp. A R0 situation would only have been achievable with a destruction of the face. Therefore the wound was closed by mesh graft and a subsequent radiation therapy was started. Six months after radiation there is no histological evidence for a recurrence of the MAC. This case report demonstrates that MAC can develop to an extreme dimension notwithstanding its clinical invisibility. Due to the rareness of the tumor only little is known about etiology and pathogenesis. An induction by UV exposure or ionising radiation is discussed. If PDT had an influence of the appearance of the MAC in this case, remains speculative.

Verrucous growth on the vulva

A 45-year-old retropositive female presented to us with recurrent painful ulcers on the external genitalia that were clinically suggestive of herpes genitalis. Incidentally, we noticed few raised lesions on the labia majora that the patient was unaware of [Figure 1]. Because she was recently diagnosed with human immunodeficiency virus infection, her CD4 counts were not available. Clinical examination revealed multiple soft warty growths on the labia majora. A biopsy from one of the lesions was sent for histopathological examination, which showed features as shown in Figure 2. Figure 1 Clinical picture showing a brownish verrucous growth on the vulva Figure 2 Showing papillae lined by squamous epithelium with hyperkeratosis, parakeratosis and a central fibrovascular core, (H&E, 200×) What is your diagnosis? Biopsy showed a raised papillary verrucous lesion with papillae lined by squamous epithelium showing hyperkeratosis, focal parakeratosis and acanthosis with a central fibrovascular core. No koilocytes were seen. Squamous papilloma of the vulva. DISCUSSION Squamous papilloma of the vulva is a benign epithelial neoplasm commonly seen in about 1% of middle-aged women.[1] Altmeyer et al.[2] first described these small projections as pseudocondylomata of the vulva. It has been reported under a variety of names such as benign squamous papillomatosis,[3] vulval squamous papillomatosis, vestibular papillomatosis, hirsuties papillaris vulvae, hirsutoid papillomas of the vulva, micropapillomatosis labialis and squamous vestibular micropapilloma. The abundance of names reflects the uncertain origin of this condition. Squamous papilloma usually presents as a solitary verrucous exophytic growth on the vulvar vestibule. It is often considered to be a variant of skin tags by some authors. Although usually asymptomatic, rarely, it may be associated with pruritus and a burning sensation. The significance of vulvar squamous papillomatosis is subject to controversy. Some authors consider the lesions as normal anatomical variants of the vestibular mucosa.[4–6] Others, however, believe that the lesions are human papilloma virus-associated as they resemble genital warts,[7] Of late, various molecular biology techniques have been used to clarify the origin of squamous papilloma, but the results have not been unanimous. In order to facilitate the differentiation between vestibular papillomatosis and genital warts, several clinical parameters have been proposed by Moyal-Barracco et al.[8] Vestibular papillae are pink-colored (same as that of adjacent mucosa), soft, linear and symmetrically distributed. The base of individual vestibular papillae projections remain separate and no circumscribed whitening is seen by the acetic acid test. Condyloma acuminatum, on the other hand, is firm and randomly localized. The color of the condyloma acuminatum lesions can vary and individual papillary projections often coalesce in a common base. In most cases of condyloma acuminate, whitening can be observed by the acetic acid test.[8] Apart from a condyloma acuminata, other differential diagnosis considered in our patient were bowenoid papulosis and seborrhoeic keratosis, each of which were aptly excluded by the absence of typical histological findings such as koilocytes and keratin horn cysts. In our patient, the typical bilateral distribution of squamous papilloma was not seen. Our patient being retrovirus positive had only a unilateral distribution of hyperpigmented soft warty lesions on the labia majora. Because the lesions were asymptomatic and not of much concern to the patient, no treatment was offered.

Cornu cutaneum at an unusual site

AbstractCutaneous horn (cornu cutaneum) is a clinical diagnosis referring to a conical projection above the surface of the skin that resembles a miniature horn. The base of the horn may be flat, nodular or crateriform. The horn is composed of compacted keratin. Various histologic lesions have been documented at the base of the keratin mound and histological confirmation is often necessary to rule out malignant changes. Tenderness at the base of the lesion and lesions of larger size favour malignancy. Malignancy is present in 16-20% of the cases with squamous cell carcinoma being the most common type. We report a young male patient with a keratin horn on the right index finger tip.

Cornu cutaneum at an unusual site

Cutaneous horn (cornu cutaneum) is a clinical diagnosis referring to a conical projection above the surface of the skin that resembles a miniature horn. The base of the horn may be flat, nodular or crateriform. The horn is composed of compacted keratin. Various histologic lesions have been documented at the base of the keratin mound and histological confirmation is often necessary to rule out malignant changes. Tenderness at the base of the lesion and lesions of larger size favour malignancy. Malignancy is present in 16-20% of the cases with squamous cell carcinoma being the most common type. We report a young male patient with a keratin horn on the right index finger tip.

A very large keratin horn of the hand

A very large keratin horn of the hand

A very large keratin horn of the hand

A case of a very large cutaneous horn of the dorsum of the hand is documented.

Myringitis Secondary to a Keratin Horn

A 53-YEAR-OLD white man who was seen in the clinic had suffered from pain and discharge in his right ear for two days. He denied previous ear trouble and reported his hearing to be subjectively normal. He had had a recent cold. Other than the abdominal complaints for which he was hospitalized, his general health in the recent past had been good. He denied trauma to, or getting water in, his ears. There was no history of previous external otitis, otitis media, foreign object in the ears, and no dermatological problem. Examination showed an upper respiratory infection of moderate severity and retraction of both ear drums, but no evidence of fluid in the middle ears. On the right side, the drum was quite reddened and inflamed, especially in the superior portion and along the handle of the malleus. Attached to the superior portion of the external surface of the right