Immunohistochemistry for CD117 (KIT) is effective in distinguishing cutaneous adnexal tumors with apocrine/eccrine or sebaceous differentiation from other epithelial tumors of the skin

Primary Cutaneous NUT Carcinoma: Clinicopathologic and Genetic Study of 4 Cases

WHO Classification of Skin Tumors, fifth edition (2023) has newly described primary cutaneous NUT carcinoma; however, information on this cancer type remains scarce. Herein, we performed clinicopathologic and genetic analyses of 4 cases. Four elderly women (median age 77 y, range: 68 to 82 y) were included. The median tumor size was 12.5 (10 to 40 mm). Tumors were located on the scalp, temple, thigh, and palm. Two (50%) patients presented with regional lymph node metastases. Neither distant metastasis nor mortality was observed during patient follow-up of 10.5 (3 to 15) months. Sanger, panel DNA and whole-exome RNA sequencing revealed BRD3::NUTM1 (n=2) and BRD4::NUTM1 (n=2) fusions. Histology of BRD3 -rearranged tumors revealed an epidermal connection, relatively small tumor nests, and ductal or intracytoplasmic luminal formation, whereas that of BRD4 -rearranged tumors revealed large solid nests comprising discohesive tumor cells. NUT, cytokeratins, p63, EMA, TRPS1, c-MYB, CD56, and INSM1 were immunoexpressed to varying degrees in all (100%) tumors. Furthermore, diffuse SOX10 expression was common (3/4, 75%). The literature review of five previously described cases revealed women predominance, no recurrence, frequent BRD3::NUTM1 fusions, and histology of ductoglandular structures. Our study findings and literature suggest elderly women predominance, relatively frequent BRD3::NUTM1 fusions, histopathologic ductoglandular differentiation, absence of abrupt keratinisation, and a characteristic immunoprofile in primary cutaneous NUT carcinoma, unlike in that of other organ. No distant metastasis or disease-associated mortality was seen in all cases with limited follow-up.

Carcinoid-Like Cell Arrangements in Basal Cell Carcinoma: A Study of 11 Cases

Background. Carcinoid-like pattern in basal cell carcinoma is extremely rare and has only been documented in a textbook. The aim of this study is to reveal the characteristics of the carcinoid-like pattern in basal cell carcinoma as well as to establish the concept of the tumor pattern. Methods. Of 355 basal cell carcinoma cases (355 lesions of 308 patients), 11 tumors with histopathological features of carcinoid-like pattern were retrieved. Results. The patients included 5 males and 6 females with a median age of 73 years (range 38-86 years). Of the 11 lesions, 10 were observed on the head. Histopathologically, a carcinoid-like pattern with branching and anastomosing of trabecular structures was observed in 30% to 95% of the tumor area. No differentiation to sebocytes was observed in any of the tumors. The tumors were well-circumscribed, although 3 lesions contained an infiltrative-type component as well. The carcinoid-like pattern areas in all 11 lesions exhibited diffuse BerEP4 immunoexpression but no KIT, synaptophysin, or vimentin expression. Keratin 20-positive Merkel cells were not observed in the tumor areas. Conclusions. Basal cell carcinoma can show a carcinoid-like pattern cell arrangement. Based on the histopathological and immunohistochemical findings from our study, we collectively conclude that the carcinoid-like pattern in basal cell carcinoma does not seem to represent sebaceous mantle differentiation. Carcinoid-like pattern basal cell carcinoma can be distinguished from other tumors by the favorite site of the head, the co-existence of conventional basal cell carcinoma components, lack of sebaceous differentiation, and diffuse BerEP4 immunoexpression.

Breast cancer with scalp metastases: a case report

BACKGROUND

While breast cancer is the most common cancer in women, cutaneous metastases are rare in breast cancer. Additionally, scalp involvement in breast cancer metastasis is extremely rare. That being said, scalp lesions should always be thoroughly investigated to distinguish metastatic lesions from other neoplasms.

CASE PRESENTATION

A 47-year-old female Middle-Eastern patient presented with metastatic breast cancer in the lungs, bone, liver, and brain with no signs of multiple organ failure, in addition to cutaneous metastases, including the scalp. Between 2017 and 2022, she was managed through modified radical mastectomy, radiotherapy, and several lines of chemotherapy. She presented in September of 2022 with enlarging scalp nodules, which started developing 2 months prior to her presentation. Physical examination revealed firm, non-tender, and immobile skin lesions. Magnetic resonance imaging scan of the head showed soft tissue nodules in different sequences. A punch biopsy was taken from the largest scalp lesion and showed metastatic invasive ductal carcinoma. A panel of immunohistochemistry stains was applied, because a single specific marker for differentiating primary cutaneous adnexal tumors or other malignant neoplasms from breast cancer has not yet been identified. The panel showed positive estrogen receptor 95%, progesterone receptor 5%, negative human epidermal growth factor receptor 2, positive GATA binding protein 3, positive cytokeratin-7, negative P63, and negative KIT (CD117).

CONCLUSION

Breast cancer metastases to the scalp are extremely uncommon. When a scalp metastasis is present, it might be the only symptomatic sign of disease progression or widespread metastatic lesions. However, such lesions warrant a comprehensive radiologic and pathologic workup to rule out other possibilities of skin pathologies, such as sebaceous skin adenocarcinoma as it effects the management plan.

The Utility of Myoepithelial Cell Layer Identification in Adnexal Carcinomas

ABSTRACT

The distinction of metastatic carcinomas to the skin (MCS) from cutaneous adnexal carcinomas can pose a significant diagnostic challenge. The differentiation between (MCS) from a primary cutaneous adnexal tumor is one of the most difficult tasks in the field of dermatopathology, and immunohistochemistry has only been partially helpful in solving this problem. In routine diagnostic surgical pathology, it is essential to identify the myoepithelial cell layer by immunohistochemistry to distinguish between an in situ and invasive breast carcinomas and when establishing the presence of microinvasion. The purpose of this study was to evaluate the role of myoepithelial cell layer expression in difficult cases of cutaneous adnexal carcinomas in which histologically it was challenging to separate them from MCS. We studied 38 adnexal carcinomas and evaluated them for myoepithelial markers to confirm the primary nature of the neoplasm. The used markers to search for myoepithelial cell layer retention included calponin, p63, and smooth muscle actin. Of the 38 cases, we found that 13 cases showed myoepithelial layer retention, confirming the primary cutaneous origin of the neoplastic process. The results of our study suggest that the presence of an identifiable retention of the myoepithelial cell layer in adnexal carcinomas could be a useful adjunct observation in the diagnosis of primary adnexal carcinomas, especially in the clinical setting of a questionable primary adnexal versus metastatic neoplasm.

Trichilemmal cysts with proteinaceous material: A potential diagnostic pitfall

BACKGROUND

Cysts of the skin are observed frequently and their diagnoses are generally straightforward. However, atypical cystic lesions for which differentiation is indistinct have been noted.

METHODS

We examined five cases of trichilemmal cyst with proteinaceous material (TCPM), which required differentiation from sweat duct/gland tumors. We investigated the histopathological findings of TCPMs and evaluated the immunohistochemical expression of cytokeratin (CK) 10, CK13, CK17, CK19, CD8, and CD117. Immunohistochemical analysis was performed on the five TCPMs, 10 trichilemmal cysts (TCs), five clear cell hidradenomas, five poroid hidradenomas, and cutaneous normal adnexa.

RESULTS

Apoptotic cells were present in the cyst wall with a small amount of keratin or calcification in the cavity of TCPMs. The TCPMs and TCs were negative for CK19 and CD117, whereas clear cell hidradenoma and poroid hidradenoma were positive for CK19 and CD117. The restricted positivity for CK10 was detected in the suprabasal layers of the cyst walls of TCPMs and TCs. The immunostaining patterns of TCPMs and TCs were similar to those of normal follicular isthmus.

CONCLUSIONS

The histopathological findings with characteristics of TCs and a panel of immunohistochemical antibodies including CD117, CK19, and CK10 contributed to a correct diagnosis of TCPM. This article is protected by copyright. All rights reserved.

A case of trichogerminoma: a rare cutaneous follicular neoplasm

Trichogerminoma, first described by Sau et al. in 1992, is a rare cutaneous adnexal neoplasm of the hair germ cell and usually associated with benign clinical course and favorable outcome. About 30 cases have been reported, all with similar histological features. However, due to a small but potential risk of malignancy, complete excision of the tumor is the treatment of choice. There is still controversy over its inclusion into the spectrum of trichoblastoma.

Herein, we report an additional case occurring in the left buttock of a 47-year-old female, presenting with a subcutaneous solitary nodule composed of lobules of basaloid cells, with peripheral palisading and round cell nests or "cell balls" arranged in the central part. The lobules are separated by a fibrous or myxoid stroma. There are no clefts separating the tumor cells and surrounding stroma, but clefts separating stroma by the surrounding adipose tissue can be seen. Typical mitotic figures are frequently present (4-5 per 10 high-power fields). Immunohistochemistry shows the tumor cells are positive for pan-CK (AE1/AE3), CK5/6, p40, GATA 3, whereas they are negative for CK7, CK20, chromogranin A, synaptofisin, androgen receptor, estrogen receptor, and calretinin. Staining for CK20, synaptofisin, and chromogranin A detect Merkel cells scattered within the lobules. Ki67 highlights a nuclear proliferative rate of about 20%.

Trichogerminoma should be distinguished from other trichogenic tumors made up of basoloid cells or hair follicular differentiation. The mainly differential diagnosis includes trichoblastoma, trichoepitelioma, tricholemmoma, and basal cell carcinoma.

Herein, we report a case of trichogerminoma which, unlike the cases previously reported, showed numerous mitotic figures and a higher Ki67 nuclear proliferative rate.

Sweat-gland carcinoma with neuroendocrine differentiation (SCAND): a clinicopathologic study of 13 cases with genetic analysis

Low-grade neuroendocrine carcinoma of the skin (LGNECS) was proposed in 2017 as a new primary cutaneous neoplasm with neuroendocrine differentiation; however, it is not yet well known due to its rarity. Herein, we perform a detailed clinicopathologic analysis of 13 cases as well as panel DNA sequencing in three cases. The study included 12 males and 1 female with a median age of 71 (43-85) years. All lesions occurred on the ventral trunk. The mean tumor size was 2.2 (0.8-11.0) cm. The histopathology resembled that of well-differentiated neuroendocrine tumors (NETs) in other organs, but intraepidermal pagetoid spreading was seen in 8 (61.5%) cases and stromal mucin deposits in 4 (30.8%). Immunoreactivity for CK7, CK19, EMA, BerEP4, CEA, chromogranin A, synaptophysin, INSM1, GCDFP15, GATA3, ER, and bcl-2 were present in varying degrees in all tested cases. PTEN c.165-1G>A splice site mutation was detected by panel sequencing in one case, and GATA3 P409fs*99 and SETD2 R1708fs*4 in another case. Lymph node metastasis was seen significantly in cases with tumor size >2.0 cm [8/8 (100%) vs. 1/5 (20%)]. All three cases with size >3.0 cm were in unresectable advanced-stage [3/3 (100%) vs. 1/10 (10%)], and two of the three patients succumbed to the disease. The two cases of death revealed mild nuclear atypia (mitosis: 1/10 HPFs) and moderate nuclear atypia (2/10 HPFs). Thus, tumor size would be a better prognostic factor than nuclear atypia, mitotic count, and Ki67 index, unlike in NETs. These clinicopathologic and immunohistochemical features would represent the characteristics as skin adnexal tumors with apocrine/eccrine differentiation rather than NETs; therefore, we rename it as sweat-gland carcinoma with neuroendocrine differentiation (SCAND).

Low-Grade Neuroendocrine Carcinoma of the Skin (Primary Cutaneous Carcinoid Tumor) as a Distinctive Entity of Cutaneous Neuroendocrine Tumors: A Clinicopathologic Study of 3 Cases With Literature Review

There is scarcity of information on primary cutaneous low-grade neoplasms commonly known as carcinoid tumors, owing to their rarity. The authors present 3 cases that were named "low-grade neuroendocrine carcinoma of the skin" (LGNECS). These occurred in the dermis and subcutis of the anterior chest or the inguinal region in the elderly. Histologically, the tumors showed infiltrating proliferation of nests of various sizes, with low-grade neuroendocrine cytologic features but without mucin production. All cases exhibited varying degrees of intraductal tumor components. On immunohistochemical examination, these tumors expressed estrogen receptor alpha, progesterone receptor, androgen receptor, gross cystic disease fluid protein 15, mammaglobin, and GATA3 as well as neuroendocrine markers. Although a literature review revealed 8 additional possible cases with no evidence of other diseases, it was difficult to determine if these were true cases of LGNECS, because of the limited information available. Based on its characteristic histologic features and immunoprofile, it can be proposed designating LGNECS as a distinct entity among cutaneous neuroendocrine tumors. Otherwise, such tumors could be misdiagnosed as mammary carcinomas (particularly when involving the skin of the breast) or as metastatic visceral neuroendocrine tumors of the skin.

Topics in histopathology of sweat gland and sebaceous neoplasms

This article reviews several topics regarding sweat gland and sebaceous neoplasms. First, the clinicopathological characteristics of poroid neoplasms are summarized. It was recently reported that one-fourth of poroid neoplasms are composite tumors and one-fourth are apocrine type lesions. Recent progress in the immunohistochemical diagnosis of sweat gland neoplasms is also reviewed. CD117 can help to distinguish sweat gland or sebaceous tumors from other non-Merkel cell epithelial tumors of the skin. For immunohistochemical differential diagnosis between sweat gland carcinoma (SGC) other than primary cutanesous apocrine carcinoma and skin metastasis of breast carcinoma (SMBC), a panel of antibodies may be useful, including p63 (SGC⁺ , SMBC^- ), CK5/6 (SGC⁺ , SMBC^- ), podoplanin (SGC⁺ , SMBC^- ) and mammaglobin (SGC^- , SMBC⁺ ). Comparison of antibodies used for immunohistochemical diagnosis of sebaceous carcinoma (SC) suggests that adipophilin has the highest sensitivity and specificity. Some authors have found that immunostaining for survivin, androgen receptor and ZEB2/SIP1 has prognostic value for ocular SC, but not extraocular SC. In situ SC is rare, especially extraocular SC, but there have been several recent reports that actinic keratosis and Bowen's disease are the source of invasive SC. Finally, based on recent reports, classification of sebaceous neoplasms into three categories is proposed, which are sebaceoma (a benign neoplasm with well-defined architecture and no atypia), borderline sebaceous neoplasm (low-grade SC; an intermediate tumor with well-defined architecture and nuclear atypia) and SC (a malignant tumor with invasive growth and evident nuclear atypia).

MYB, CD117 and SOX-10 expression in cutaneous adnexal tumors

BACKGROUND

Elevated MYB expression has been documented in adenoid cystic carcinoma (ACC), cylindroma, and spiradenoma, but the specificity of this finding is unknown. CD117 and SOX-10 expression also occurs in some cutaneous adnexal tumors. This study assesses MYB, CD117 and SOX-10 expression in cutaneous adnexal tumors.

METHODS

Retrospective analysis of 184 benign adnexal tumors (140 eccrine/apocrine, 40 follicular and 10 sebaceous), and 30 malignant adnexal tumors was performed with MYB, SOX-10 and CD117 immunostaining.

RESULTS

In the benign adnexal tumors, 16% (23/140) significantly expressed MYB. MYB expression was limited to cylindromas and to a lesser extent, spiradenomas in the benign cohort. Elevated MYB expression was detected in mucinous carcinoma, endocrine mucin-producing sweat gland carcinoma and 1 and 4 cases of extramammary Paget's disease (EMPD) in the malignant cohort. CD117 and SOX-10 had similar overall positivity rates in benign apocrine and eccrine tumors (45% and 68% respectively), and were generally negative in other benign and malignant adnexal tumors.

CONCLUSION

Expression of MYB appears limited to a small number of cutaneous adnexal tumors, including cylindromas, spiradenomas, ACCs, mucinous carcinoma, endocrine mucin-producing sweat gland carcinoma and some cases of EMPD.

Expression of C-KIT, CD24, CD44s, and COX2 in benign and non-invasive apocrine lesions of the breast

Benign apocrine metaplasia (AM) of the adult breast is a very common, but enigmatic lesion. It has been speculated that AM might be a precursor of malignancy or an indicator of a susceptibility of the breast tissue to develop neoplasia, mainly based on comparing the frequency of AM in breast cancer and non-breast cancer patients [1]. Studies using comparative genomic hybridization have supported this by showing similar molecular alterations in benign and malignant apocrine lesions [2]. Few studies, however, have compared expression of biomarkers involved in tumor progression in AM and progressively more advanced atypical apocrine lesions. The expression of C-KIT, COX2, CD24, and CD44s was evaluated by immunohistochemistry in formalin-fixed, paraffin-embedded material of 9 AM, 20 apocrine ductal intraepithelial neoplasia (DIN1c-3) and 40 atypical apocrine lesions (not qualifying for DIN1c-3) and compared to expression of the same biomarkers in adjacent normal ductal epithelium. Of the 66 apocrine lesions, 62 (94 %) did not express C-KIT compared to 4/63 (6 %) of the normal glands (Fisher's exact, p < 0.001). COX2 was expressed in a significantly higher proportion of apocrine lesions than of normal glands (49 vs. 14 %, p < 0.001), and the number of apocrine lesions positive for CD24 was found to be higher with increasing aggressiveness of the lesions (Spearman, p < 0.001). In conclusion, benign and non-invasive proliferative apocrine lesions of the breast display immuno-phenotypical characteristics previously ascribed mainly to malignant transformation. This could lend support to the theory that AM is an early step towards malignant transformation, albeit associated with slow progression to carcinoma.

[What's new in oncodermatology in 2015?]

Oncodermatology is the topic of constant innovation since 5 years. These innovations have drammatically modified the prognostic of skin cancers and induced a change in the paradigm that drives the whole oncology. Once again in 2015, melanoma is the key topic of scientific communication, with promising results. However, unmet clinical needs must be kept in light. Some diseases, such as squamous cell carcinoma or cutaneous lymphoma remain poorly evaluated. This article was designed as a review of litterature. All keywords of oncodermatology were searched in the main journals of dermatology, oncology and internal medicine. Despite methodologic restrictions, the number of articles imposed a choice based on opinion. The final goal was to transmit author's enthousiasm and the most important results.