Clinical and Histopathologic Study of Apocrine-Type Mixed Tumor of the Skin.

ABSTRACT: Mixed tumor of the skin (MTS) is a tumor characterized by folliculosebaceous-apocrine differentiation. Because of the wide range of histological variations, understanding the unique features of MTS can help improve diagnosis. This study describes the histopathological characteristics of MTS, mainly apocrine-type MTS (AMT), using 166 cases of AMT. We found that nodular aggregates of myoepithelial cells, mucinous changes in the stroma, and follicular differentiation were standard characteristic features of MTS. Among the cases studied, 67% showed prominent follicular germinative cells and 40% showed prominent lipomatous metaplasia in the stroma. These cases often pose difficulties for the diagnosis of AMT because of insufficient evidence of sweat glands or myoepithelial cell differentiation. This is the first study to examine how the histological features of AMT change as the tumor extends deeper into the dermis. We found that the proportion of AMT with folliculosebaceous differentiation and large lumina increased as it got deeper into the dermis. Histopathological diagnosis of MTS is vital because the clinical symptoms lack specificity. This study enhances our understanding of the histopathological characteristics of MTS.

Folliculosebaceous Cystic Hamartoma Arising in Miescher-Type Melanocytic Nevi.

ABSTRACT: Folliculosebaceous cystic hamartoma (FSCH) is a rare cutaneous hamartoma consisting of dilated folliculosebaceous units associated with mesenchymal elements. Ansai et al reported that distinctive features of Miescher-type melanocytic nevi (MMCNs) accompanied 4.6% of FSCH; however, there have been no data about how often FSCH features accompany MMCNs. In this study, we used 7829 cases that had been histopathologically diagnosed as MMCNs of the face, neck, and scalp at the Department of Dermatopathology, Nippon Medical School Musashi Kosugi Hospital and observed whether features of FSCH accompanied them. Of the resected MMCNs, 274 of 7829 (3%) were accompanied by features of FSCH. The nose was the most common resection site, followed by the eyebrow area, ear, and cheek. The coexistence rate for the nevi on the nose and features of FSCH was as high as 10%-20%, and its rate increased with age. We found that FSCH appears mostly in seborrheic areas, such as the nose and cheek, which are rich in normal sebaceous glands. This suggests that nevi, especially on and around the nose, may induce FSCH or similar lesions.

Serum Interleukin-18 Provides a Clue to the Diagnosis of Adult-Onset Still's Disease: Findings from 6 Japanese Patients with Adult-Onset Still's Disease.

BACKGROUND: Adult-onset Still's disease (AOSD) is a systemic autoinflammatory disorder accompanied by skin eruption. However, typical skin eruptions, such as evanescent, salmon-pink erythema, are not specific to AOSD and dermatologists often face difficulty in diagnosing AOSD. In this study, we examined serum IL-18 levels as well as IL-6, ferritin and C-reactive protein in 6 Japanese patients with AOSD. METHODS: Serum levels of IL-6 and IL-18 were evaluated in the acute phase and at the time of remission. Serum levels of IL-6 were analyzed using a commercial chemiluminescent enzyme immunoassay (CLEIA; SRL, Tokyo, Japan). Serum IL-18 levels were measured using a commercial ELISA kit (Medical & Biological Laboratories Co., LTD. Nagoya, Japan). RESULT: In active AOSD, serum ferritin levels and CRP levels were above normal range in 6 patients. In remission, serum ferritin levels of 3 patients were slightly above the normal range, while CRP serum levels of 6 patients were all normalized. Serum IL-18 levels were markedly elevated in 5 cases during the acute phase. In remission, serum IL-18 levels remained at higher values than the normal range in 5 cases. Serum IL-6 levels were also highly elevated in 5 patients in active AOSD and became normalized in remission except in case 2. CONCLUSION: High levels of serum IL-18 will be a clue to the diagnosis of AOSD. CRP is also useful biomarker for monitoring disease activity compared with IL-6 and IL-18.

What Is a Solitary Keratoacanthoma? A Benign Follicular Neoplasm, Frequently Associated with Squamous Cell Carcinoma.

We present histopathological criteria for diagnosing keratoacanthoma (KA). In KA, four histological stages are recognized, which are the early/proliferative stage, well-developed stage, regressing stage and regressed stage. In diagnosing KA, we emphasize that KA consists of the proliferation of enlarged pale pink cells with ground glass-like cytoplasm without nuclear atypia, other than crateriform architecture. KA sometimes exhibits malignant transformation within the lesions. We describe the characteristics of benign and malignant epithelial crateriform tumors that should be differentiated from KA. We also present the data of histopathological diagnosis of lesions clinically diagnosed as KA, its natural course and related lesions after partial biopsy, and incidence of crateriform epithelial neoplasms. Based on these data, we recommend complete excision of the lesion when KA is clinically suspected, especially when the lesion is located on a sun-exposed area of an elderly patient. If complete excision is impossible, partial excision of a sufficient specimen with intact architecture is required. In such a case, however, careful investigation after biopsy will be needed, even if the histopathological diagnosis is KA, because there is some possibility that a conventional SCC lesion remains in the residual tissue.

Infantile Myofibroma: Case Report and Review of the Literature.

We report a case of solitary infantile myofibroma (IM) with partially CD34-positive neoplastic cells on the back of a newborn boy. Ultrasonography showed a multilocular mass with a hypoechoic center surrounded by an isoechoic rim. Histopathological analysis revealed that the lesion was composed of small, round cells that were tightly packed and uniform. The cells had oval nuclei and were pale, CD34-positive, and richly cellular. They had interlacing fascicles of spindle cells with features of myofibroblasts with α-smooth muscle actin positivity. We speculate that neoplastic cells in most IMs differentiate towards myofibroblasts. However, in rare cases, their differentiation is more primitive and they express CD34, with or without α-smooth muscle actin expression.

Skin Testing to Identify Safe Drugs for Patients with Rocuronium-Induced Anaphylaxis.

Among patients who develop anaphylaxis during anesthesia, anaphylaxis caused by a neuromuscular blocking agent has the highest incidence. In patients who developed IgE-mediated anaphylaxis, and cross-reactivity among NMBAs is a concern in subsequent anesthetic procedures. We present a patient who developed rocuronium-induced anaphylaxis in whom the skin prick test (SPT) and intradermal test (IDT) could identify a safe drug to use in the subsequent anesthetic procedure. A 32-year-old female developed anaphylactic shock at the induction of general anesthesia. She recovered by administration of hydrocortisone and epinephrine. Skin tests including the SPT followed by the IDT revealed rocuronium as the drug that caused anaphylaxis and vecuronium as a safe drug to use for the subsequent general anesthesia. She safely underwent surgery with general anesthesia using vecuronium one month after the skin testing. There are not many reports on the effectiveness of the SPT followed by IDT in identifying the causative drug as well as a safe drug to use in the subsequent anesthetic procedure following anaphylaxis during anesthesia. The usefulness of the SPT should be re-evaluated.

A Case with Unique Dermoscopic Findings: Collision of an Apocrine Gland Cyst and a Trichoblastoma.

We report a case of a blue-black nodule on the left upper eyelid of a 77-year-old woman. Dermoscopic examination of the lesion revealed a purple or purple-red homogenous opaque area like that often observed in apocrine gland cysts and a yellow-whitish homogenous structure with arborizing vessels. After resection of the tumor, a final diagnosis of collision of an apocrine gland cyst and a trichoblastoma was made. We should note the possibility that trichoblastoma may exhibit a yellow-whitish homogenous structure in dermoscopy.

Histopathological diagnosis of epithelial crateriform tumors: Keratoacanthoma and other epithelial crateriform tumors.

Keratoacanthoma (KA) is a unique and distinct clinicopathological entity, although there is often confusion regarding its differentiation from other types of crateriform tumors. In this study, the clinicopathological features of 380 epidermal crateriform tumors with a central keratin plug were re-examined and the tumors were histologically classified into seven types: (i) crateriform verruca; (ii) crateriform seborrheic keratosis; (iii) KA; (iv) KA with a conventional squamous cell carcinoma (SCC) component (KA-like SCC and KA with malignant transformation); (v) crateriform Bowen's disease; (vi) crateriform SCC arising from solar keratosis; and (vii) crater form of infundibular SCC. Our study proved that incidence of SCC developing in KA lesions was 17.4%. The incidence rate differed depending on a patient's ages: 8.3% in patients less than 70 years of age and 24.3% in those aged 70 years and older. Nearly all of the malignant crateriform neoplasms (94.7%) occurred on sun-exposed areas. Lesions on the face included 138 KA (59.5%), 65 malignant crateriform neoplasms (28%) and 29 benign crateriform neoplasms (12.5%). We conclude that KA is not a variant of SCC, but a benign and frequently regressing proliferative lesion or borderline neoplasm, although there is the potential for SCC to arise within KA. Because the incidence of SCC developed in KA lesions and the incidence of other malignant crateriform neoplasms are higher in patients aged 70 years and older, KA-like lesions on sun-exposed areas over 70 should be assessed carefully in consideration of the potential risk of malignancy.

Clinicopathological study of crateriform verruca: Crateriform epithelial lesions histopathologically distinct from keratoacanthoma.

Keratoacanthoma (KA) is a distinct clinicopathological entity, but it is often confused with other crateriform tumors. This study re-examined the clinicopathological features of 380 crateriform epithelial tumors with a central keratin plug. Seventy-six tumors (20%) had histopathological features that differed from solitary KA and were more verruca-like, and we designated these lesions as crateriform verruca (CFV). We performed clinicopathological re-examination of these neoplasms with a crateriform architecture and epithelial lip-like structures similar to KA, which also displayed histopathological features reminiscent of verruca vulgaris, such as finger-like exophytic projections with hyperkeratosis and acanthosis, focal hypergranulosis and arborization. Clinical data on CFV were also summarized. The main histopathological differences from KA were that CFV showed proliferation of keratinocytes with a similar size and regular arrangement, and the base of CFV was well demarcated without endophytic growth. Interestingly, some CFV were partly composed of epithelial cells with large pink cytoplasm in the upper malpighian layer between papillomatous projections. Furthermore, areas of trichilemmal-like keratinization without formation of the granular layer were seen in some lesions. These types of CFV were hardly distinguishable from KA, unless it is recognized that CFV may contain trichilemmal keratinization-like areas accompanied by large epithelial cells with eosinophilic cytoplasm. We have proposed the term CFV for these verrucous neoplasms to differentiate them from KA.

Case of Merkel cell carcinoma with squamous cell carcinoma possibly arising in chronic radiodermatitis of the hand.

We report a case of Merkel cell carcinoma (MCC) on the dorsal aspect of the right middle finger associated with multiple squamous cell carcinomas (SCC) possibly arising in chronic radiation dermatitis of the hand of an 80-year-old surgeon. In spite of resection of the primary lesion and right axillary lymph nodes, he died of the tumor 5 months after the first visit. Cutaneous and lymph node lesions of MCC were negative for Merkel cell polyoma virus (MCPyV) by immunostaining using monoclonal antibody (CM2B4) and anti-large T antigen of MCPyV polyclonal antibody, and real-time polymerase chain reaction. Several differences in clinicopathological findings have been found between MCPyV-positive cases and negative ones. Several authors have reported that MCPyV-negative cases have a worse prognosis than MCPyV-positive ones. Furthermore, in cases of MCC associated with SCC, most tumors have been reported to be MCPyV-negative. We should pay more attention to the relationship between the carcinogenesis of MCC and ionizing irradiation.

Case of anaphylaxis due to tetracycline hydrochloride.

A 17-year-old Japanese woman showed anaphylaxis after taking tetracycline hydrochloride, pyridoxal phosphate, flavin adenine dinucleotide sodium and ascorbic acid. Prick tests were performed for these suspicious drugs and anaphylaxis due to tetracycline hydrochloride was diagnosed.

Nodular-type lichen myxedematosus: a case report.

An 18-year-old Japanese woman noticed a progressive appearance of nodules on both forearms and on the left cubital fossa and left thigh one year before her initial consultation at our department. Physical examination showed elastic hard, slightly elevated, shiny and yellowish to skin-colored nodules of 6 to 10 mm in size on her extremities. From laboratory and histopathological findings, nodular-type lichen myxedematosus was diagnosed and nodules showed complete remission following local injection of triamcinolone acetonide.