Does Immunohistochemistry Add to Morphology in Differentiating Trichoepithelioma, Desmoplastic Trichoepithelioma, Morpheaform Basal Cell Carcinoma, and Microcystic Adnexal Carcinoma?

BACKGROUND: The distinction among cutaneous basaloid neoplasms such as trichoepithelioma (TE), desmoplastic trichoepithelioma (DTE), morpheaform basal cell carcinoma (MBCC), and microcystic adnexal carcinoma (MAC) can be difficult, especially in superficial biopsies. As the treatment plan of each entity is different, accurate characterization is important for appropriate management. While TE and DTE are benign neoplasms with indolent behavior, MBCC and MAC are typically locally aggressive. The expression of several recently described immunohistochemical (IHC) markers, including p40, IMP3, and ProEx C, has not been adequately established in cutaneous neoplasms. We explored the potential utility of a broad IHC panel, including previously reported and novel markers to differentiate TE, DTE, MBCC, and MAC. DESIGN: A total of 35 archival cases [TE (n=14), DTE (n=9), MBCC (n=6), and MAC (n=6)] were stained with 9 IHC markers: p40, IMP3, ProEx C, p16, CK20, Ki-67, androgen receptor, D2-40, and beta-catenin. Tumors with >5% immunoreactivity were scored as positive. The intensity was scored on a scale from 1+ to 3+. The pattern of positivity- nuclear, cytoplasmic, membranous, or in combination; peripheral or central distribution with lesion was also recorded. RESULTS: CK20 (in contrast to prior studies) and IMP3 were negative in all cases. Likewise, with the exception of one case of TE, androgen receptor showed no immunoreactivity in all categories. No significant difference was observed in the expression of beta-catenin, p16, ProEx C, and p40 among the four groups of cutaneous neoplasms. The mean Ki-67 labeling index for MBCC (8%) was slightly higher than DTE (3%). Interestingly, the proliferation index for TE (15%) was significantly higher than that of MBCC. All six cases of MAC and 36% of TEs expressed D2-40; neither the MBCC nor DE cases showed D2-40immunoreactivity. Also, we confirmed the previously published observation of scattered CK20 positive Merkel cells in the epidermis of all cases of DTE; whereas, no Merkel cells were identified in MBCC and MAC cases. CONCLUSIONS: Except Ki-67, our IHC panel showed no significant added diagnostic utility of IHC in discriminating among TE, DTE, MBCC, and MAC. Among the four cutaneous neoplasms, DTE and MBCC show a small but discernible difference in Ki-67.

Cutaneous Human Papillomaviruses and the Risk of Keratinocyte Carcinomas.

Cutaneous human papillomavirus (cuHPV) infections may be novel targets for skin cancer prevention and treatment, but critical information regarding the development of virus-positive skin cancers following cuHPV infection has been lacking. In this study, baseline cuHPV infection was measured by serology and viral DNA detection in eyebrow hairs (EBH) and forearm skin swabs (SSW) among 1,008 individuals undergoing routine skin cancer screening exams and followed for incidence of basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cuSCC). Baseline ß-HPV detection, particularly in SSW, significantly predicted cuSCC (HR = 4.32; 95% confidence interval, 1.00-18.66), whereas serologic evidence of past ß-HPV infection was not associated with cuSCC. Less than 5% of baseline ß-HPV types detected in SSW were present in subsequent cuSCC tumors, and cuHPV detected in SSW with higher mean fluorescence intensity values were more likely to be present in cuSCC compared with those with lower levels (P < 0.001). ß-HPV-positive cuSCC occurred more often in areas of highly sun-damaged skin than did ß-HPV-negative cuSCC. Overall, no clear patterns were observed between baseline ß-HPV detection and subsequent development of BCC, or between baseline γ-HPV detection and either cuSCC or BCC. Collectively, these results demonstrate that ß-HPV detection in SSW is a significant predictor of cuSCC risk, although evidence suggests only a small subset of cuSCC is etiologically linked to ß-HPV infection. SIGNIFICANCE: ß-HPV positivity may be a useful biomarker for identifying individuals who could benefit from increased screening or novel cutaneous squamous cell carcinoma prevention strategies.

Basal cell carcinoma treated with combined ablative fractional laser and ingenol mebutate - an exploratory study monitored by optical coherence tomography and reflectance confocal microscopy.

BACKGROUND: Basal cell carcinomas (BCCs) have previously been treated off-label with ingenol mebutate (IM). Ablative fractional laser (AFL) may improve efficacy of IM by increasing drug uptake in the tumour. Optical coherence tomography (OCT) and reflectance confocal microscopy (RCM) detect BCC non-invasively. Our aim was to investigate BCC response and tolerability after combined AFL and IM treatment of low-risk BCCs. METHODS: Twenty patients with histologically verified superficial (n = 7) and nodular (n = 13) BCCs were treated with combined fractional CO2 -laser (10 600 nm) and IM 0.015% or 0.05%, the concentration depending on anatomical location. BCC response was evaluated clinically, by OCT and RCM at day 29 and 90 after first treatment, and histologically at day 90. Treatment was repeated at day 29 if BCC persisted. Local skin reactions (LSRs) were assessed using LSR scale at all visits. RESULTS: At day 29, 18/20 patients received a second treatment due to residual BCC detected clinically, by OCT or RCM. OCT and RCM presented subclinical BCCs in five of 20 cases (25%). At day 90, overall histological cure rate was 70%, corresponding to clinical (65%) and OCT/RCM (60%) cure rates, and agreement between evaluation methods was substantial (kappa ≥ 0.796, P < 0.0001). Clearance rates were similar for sBCCs and nBCCs (P = 0.354) and for lesions treated with IM 0.015% and 0.05% (P = 0.141). LSRs were tolerable, but scarring was observed in the majority of cleared patients. CONCLUSION: Two treatments of combined AFL and IM show potential to treat low-risk BCCs with acceptable tolerability. OCT and RCM show promise to detect subclinical BCCs at short-term follow-up.

Trichofolliculoma of the Eyelid Margin: A Case Report and Review of Literature.

Trichofolliculoma is a rare benign tumor of the skin, with distinct pilar differentiation and a predilection for the head and neck. To the best of the authors' knowledge, only 10 cases of eyelid trichofolliculoma has been described in the English literature. Moreover, these benign hair follicle lesions have been reported to clinically mimic eyelid malignancy. The authors report a case of a 58-year-old woman with a nodule on the eyelid margin, with typical clinical features and characteristic histopathological findings aiding the diagnosis of trichofolliculoma. Complete resection was performed to prevent recurrence. The authors also reviewed all the cases of eyelid trichofolliculoma reported in literature to highlight the demography, clinical features, and management of this rare eyelid tumor.

[Trichilemmal carcinoma in a patient with squamous cell skin cancer]. / Trikholemmal'naia kartsinoma u patsienta s ploskokletochnym rakom kozhi.

Trichilemmal carcinoma is a rare skin tumor that mainly occurs in the elderly (mean age, 71 years) and is localized in the repeatedly sun-exposed areas, most commonly on the face, scalp, neck, and dorsa of the hands. Its differential diagnosis is made with squamous cell skin cancer, clear-cell porocarcinoma, hidradenocarcinoma, and melanoma. The prognosis of trichilemmal carcinoma is most favorable than that of other skin tumors during radical removal. The paper describes a case of an 80-year-old man with long-standing trichilemmal carcinoma of the skin in the area of the shoulder joint, which is concurrent with squamous cell cancer in another area of the skin.

Feline-type cystic basal cell tumor filled with abundant melanin pigment-rich fluid in a dog.

A 2-year-old castrated male mongrel dog presented with a well-demarcated fluctuant dermal mass, located on the back of the neck. Grossly along with cystic structures filled with a black greasy fluid, when cut open. Microscopically, the mass was multi-lobulated. The lobules consisted of neoplastic basaloid cells and showed central degeneration, forming multiple central cystic structures filled with dark melanin-pigmented materials. Immunohistochemically, the neoplastic cells were strongly positive for CK14 and partially positive for CK19, but negative for CK7, CK8/18, CD34, S-100, Melan-A and α-SMA. Based on the findings, the present case was diagnosed as a feline-type basal cell tumor characterized by cystic structures filled with abundant black fluid.

Les difficultés du diagnostic : du carcinome basocellulaire aux tumeurs trichoblastiques: From basal cell carcinoma to trichoblastic tumors: a diagnostic challenge.

Basal cell carcinoma (BCC) is a very common tumor, of which the diagnosis is generally easy. Clinical prediction of histopathological subtype however is however often difficult, i.e. the majority of sclerosing BCCs believed to be morpheaform are in fact trabecular or nodular. There is a subgroup of aggressive BCCs, including trabecular (the most common), morpheaform (rare) and micronodular (very rare) subtypes. Differentiating trichoblastoma from BCC is not always easy, but there are distinctive histopathologic criteria and preferential expression of Berp4 in BCC and PHLDA1 in trichoblastoma that may be of help. The group of trichoblastic tumors comprises giant but benign trichoblastomas and trichoblastic carcinomas at the end of the spectrum (of low or high grade). In case of metastatic BCC, one must rule out trichoblastic carcinoma. Morphologic variants of BCC such as pigmented, clear cell, granular cell BCC or BCC with areas of keratinisation are not of poorer prognosis than the classic types. On the opposite, BCC with sebaceous differentiation (in fact sebaceomas) belong to the spectrum of tumors found in Muir-Torre and must be identified. Basosquamous BCCs should be treated like squamous cell carcinomas as they are more aggressive than the nodular subtype. Cet article fait partie du numéro supplément Prise en charge des carcinomes basocellulaires difficiles à traiter réalisé avec le soutien institutionnel de Sun Pharma.

Differential diagnostic significance of epithelial and stromal CD10 expression in tumors of trichogenic origin.

BACKGROUND AND OBJECTIVES: The histological differential diagnosis between benign trichogenic skin tumors and basal cell carcinoma may be challenging. We therefore set out to investigate whether expression of CD10, a cell surface protein with neutral endopeptidase activity, might be a suitable marker for the histological differential diagnosis of trichogenic skin tumors. PATIENTS AND METHODS: We immunohistochemically analyzed 119 cases of benign trichogenic skin tumors and basal cell carcinoma. These included 28 nodular and 15 sclerosing basal cell carcinomas, 21 Pinkus tumors, 20 trichoblastomas, nine trichofolliculomas, eleven trichoepitheliomas, five desmoplastic trichoepitheliomas, and ten seborrheic keratoses. RESULTS: The majority of nodular basal cell carcinomas expressed CD10 in tumor cells at the peripheral (22/28 [75 %]). On the other hand, trichoblastomas revealed peripheral CD10 expression in only 10 % (2/20) of cases, whereas 50 % showed central expression (10/20). Peripheral epithelial expression of CD10 was also found in Pinkus tumors (9/21 [42.9 %]) and trichoepithelioma (4/11 [36.4 %]). Desmoplastic trichoepithelioma showed no tumoral CD10 expression at all (0/5 [0 %]), while the majority of sclerosing basal cell carcinomas was positive for CD10 (13/15 [86.7 %]). CONCLUSIONS: Our findings suggest that epithelial expression of CD10 - and not peritumoral stromal CD10 expression, as has been postulated - may well be of differential diagnostic significance. The pattern of distribution of CD10-positive neoplastic cells in particular can be useful in the diagnosis of trichogenic tumors.

Melanotrichoblastoma: a rare pigmented variant of trichoblastoma.

Trichoblastomas are rare cutaneous tumors arising from the hair bulb and mesenchyme. Although they are benign, they can pose a diagnostic dilemma for the clinician and pathologist because they clinically and histologically mimic more common lesions such as basal cell carcinomas (BCCs) and trichoepitheliomas. It is important for the clinician and pathologist to be aware of such tumors and their variants. We present a case of a melanotrichoblastoma, an exceedingly rare variant of trichoblastoma, as well as review the current literature on the clinical presentation and histologic differentiation of these unique tumors with their more commonly seen mimics.

Co-occurrence of steatocystoma multiplex, eruptive vellus hair cysts, and trichofolliculomas.

An association between steatocystoma multiplex (SCM) and eruptive vellus hair cysts (EVHCs) has been recognized. Steatocystoma multiplex and EVHC have similar clinical features but distinctive histologic features. Rare cases of co-occurrence of these conditions have been known to occur on the trunk and the forehead. We report a rare case of the simultaneous occurrence of SCM, EVHC, and trichofolliculomas localized to the forehead.