Trichoblastoma and breast carcinoma as metachronous primary tumors: Case report.

INTRODUCTION AND IMPORTANCE: The occurrence of more than one tumor originating from the same or different organs is the definition of multiple primary tumors. According to the time of diagnosis, these tumors are classified into two types: metachronous and synchronous tumors. Trichoblastoma is a rare benign skin tumor that is rarely involved in multiple primary tumors, especially in patients with breast cancer. CASE PRESENTATION: A 60-year-old male with left breast and lateral chest wall masses. Lastly, he has been diagnosed with invasive ductal carcinoma of the left breast and chest wall trichoblastoma as metachronous primary tumors with no significant genetic background. CLINICAL DISCUSSION: With the development in the medical field, such tumors are being encountered more. Some authors suggest a relationship between these tumors and genetic mutations. Although rare trichoblastomas can be transformed into malignant tumors and get metastasized. CONCLUSION: The diagnosis and management of primary tumors can be challenging in some cases. Researchers should focus on further exploration of the genetic bases and risk factors of such tumors.

Trichoblastic Carcinoma in the Glabella Treated With Mohs Micrographic Surgery.

Trichoblastic carcinoma (TBC) is a rare adnexal neoplasm of follicular germ cell differentiation with the potential for local invasion and metastasis. Histologic features of trichoblastic carcinoma have significant overlap with trichoblastoma and basal cell carcinoma (BCC), making diagnosis difficult in some cases. Treatment strategies are not well defined and include surgical excision for localized tumors and systemic therapies for metastatic disease. We present a case of trichoblastic carcinoma clinically resembling a benign cyst that was ultimately treated with Mohs micrographic surgery (MMS).

[A case of trichoblastoma of the auricular cavity and review of the literature].

Trichoblastoma（TB） is a rare germ cell skin adnexal tumor of the hair, and it is a rare follicular tumor of the skin that differentiates from the hair germ epithelium and is often regarded as a benign skin tumorHowever, it is poorly confined and has a local infiltrative growth pattern. tb occurs in the head and neck region, especially in the face, and presents clinically as a slow growing, well-defined and elevated nodule. TB is routinely treated surgically. Due to the lack of universally accepted treatment guidelines or protocols, the recurrence rate after surgery is high, which makes clinical cure more difficult. In this study, a 65-year-old female patient was found to have a swelling with recurrent rupture and pus flow from the right external auditory canal opening and the auricular cavity. After initial misdiagnosis as otitis externa, she was treated with conventional anti-infective therapy, but her symptoms did not resolve and gradually worsened before coming to our hospital. The condition presented in this case is relativelyrare,therepre,timely and accurate diagnosis and treatment are crucial for prognosis improvement of such diseases.

Orofacial masses in domestic rabbits: a retrospective review of 120 cases from 2 institutions, 2000-2023.

Orofacial masses or swellings are a common presenting complaint in lagomorphs. Similar gross appearances of the masses can complicate clinical interpretation, and histologic review often provides the final diagnosis. Underlying causes vary from infectious to neoplastic. Although inflammatory changes are most commonly reported, various neoplasms occur, although the prevalence of specific tumor types is relatively unknown. We reviewed retrospectively 120 cases (87.5% biopsy, 12.5% autopsy) of neoplastic and non-neoplastic orofacial masses received from January 2000-February 2023 at 2 institutions: University of Guelph, Canada (Animal Health Laboratory and Department of Pathobiology), and Finn Pathologists, United Kingdom. All final diagnoses were achieved through histologic assessment. We included masses or mass-like swellings from the oral cavity, including the mandible and maxilla, and surrounding skin and soft tissues of the oral cavity and jaw. Submissions included pet and commercial (meat and fur) rabbits. Neoplastic lesions were most common (60%), including trichoblastomas, papillomas, melanocytic neoplasms, sarcomas, round-cell tumors, carcinomas (including squamous cell carcinoma), lipomas, odontogenic neoplasms, polyps, osteoma, neuroma, peripheral keratinizing ameloblastoma, and apocrine adenoma. Inflammatory diagnoses (30%) included abscesses, osteomyelitis, dermatitis, and sialadenitis. Other diagnoses (7%) included cysts, as well as hyperplastic skin and proliferative bone lesions. Three cases had no definitive diagnosis. The importance of histologic assessment in diagnosing orofacial "masses" in rabbits is highlighted, given that the most common diagnostic category overall was neoplasia.

Detection of wildtype Merkel cell polyomavirus genomic sequence and VP1 transcription in a subset of Merkel cell carcinoma.

AIMS: Merkel cell carcinoma (MCC) is frequently caused by the Merkel cell polyomavirus (MCPyV). Characteristic for these virus-positive (VP) MCC is MCPyV integration into the host genome and truncation of the viral oncogene Large T antigen (LT), with full-length LT expression considered as incompatible with MCC growth. Genetic analysis of a VP-MCC/trichoblastoma combined tumour demonstrated that virus-driven MCC can arise from an epithelial cell. Here we describe two further cases of VP-MCC combined with an adnexal tumour, i.e. one trichoblastoma and one poroma. METHODS AND RESULTS: Whole-genome sequencing of MCC/trichoblastoma again provided evidence of a trichoblastoma-derived MCC. Although an MCC-typical LT-truncating mutation was detected, we could not determine an integration site and we additionally detected a wildtype sequence encoding full-length LT. Similarly, Sanger sequencing of the combined MCC/poroma revealed coding sequences for both truncated and full-length LT. Moreover, in situ RNA hybridization demonstrated expression of a late region mRNA encoding the viral capsid protein VP1 in both combined as well as in a few cases of pure MCC. CONCLUSION: The data presented here suggest the presence of wildtype MCPyV genomes and VP1 transcription in a subset of MCC.

Nevo sebáceo de Jadassohn. Localización atípica y síndromes asociados / Nevus sebaceus of Jadassohn. Atypical location and associated syndromes

Hamartoma benigno que puede aparecer desde el nacimiento. Se localiza sobre todo en cuero cabelludo y cara; origina una placa alopécica, amarillenta, de superficie rugosa. Tiene tres etapas, una de hiperplasia epidérmica, luego una puberal con desarrollo de glándulas sebáceas y una tardía con desarrollo de tumores benignos o malignos, en especial siringocistadenoma papilífero y tricoblastomas. Puede presentarse asociado a síndromes genéticos. Su exéresis quirúrgica es objeto de controversia (AU)

Benign hamartoma that can appear from birth. It is located mainly on the scalp and face; It causes an alopecic, yellowish plaque with a rough surface. It has three stages, one of epidermal hyperplasia, then a pubertal stage with development of sebaceous glands, and a late stage with development of benign or malignant tumors, especially papillary syringocystadenoma and trichoblastoma. It can appear associated with genetic syndromes. Its surgical excision is controversial. (AU)

TRPS1: A Marker of Follicular Differentiation.

The trichorhinophalangeal syndrome type 1 (TRPS1) immunohistochemical (IHC) stain has increased in use in recent years as a marker for breast carcinomas. The TRPS1 gene is involved in various tissues, including the growth and differentiation of hair follicles. This article seeks to evaluate the IHC expression of TRPS1 in cutaneous neoplasms with follicular differentiation, such as trichoblastoma (TB), trichoepithelioma (TE), and basal cell carcinoma (BCC). IHC studies were performed on 13 TBs, 15 TEs, and 15 BCCs with an antibody against TRPS1. The study found a variable staining expression of TRPS1 in the tumor nests of TB, TE, and BCC. BCCs were distinct in that none of the BCCs demonstrated intermediate or high positivity, while TBs and TEs showed intermediate-to-high positivity in 5/13 (38%) and 3/15 (20%) of cases, respectively. We observed a distinct staining pattern among the mesenchymal cells of TB and TE. We found that TRPS1 highlighted perifollicular mesenchymal cells adjacent to the nests of TB and TE tumor cells. This staining pattern was absent in BCCs, where only scattered stromal cells were positive for TRPS1. Papillary mesenchymal bodies were also highlighted by TRPS1 in TB and TE. TRPS1 stained various parts of the normal hair follicle, including the nuclei of cells in the germinal matrix, outer root sheaths, and hair papillae. TRPS1 may be a useful IHC marker for follicular differentiation.

Expression of BerEP4 and CD10 IHC Markers in Basal Cell Carcinoma, Squamous Cell Carcinoma and Adnexal Tumours of Follicular Differentiation: A Comparative Study.

Background: Basal cell carcinoma (BCC) is the most common cutaneous malignancy. In most cases, BCC can be diagnosed by its characteristic histopathological features. The differential diagnosis includes basaloid squamous cell carcinoma (SqCC) and adnexal tumours of follicular differentiation. Cluster of differentiation 10 (CD10) and name of an immunostain (BerEP4) are reported to be useful in differentiating between them. Objectives: The primary objective was to compare the expression of BerEP4 and CD10 in BCC with that of SqCC and adnexal tumours of follicular differentiation, and the secondary objective was to evaluate the proportion of different histological subtypes of BCC. Materials and Methods: Twenty-eight cases of BCCs, 34 cases of SqCCs and 16 adnexal tumours of follicular differentiation received in the institution during the study period January 2017 to June 2018 were included in this descriptive study. Immunostaining with CD10 and BerEP4 was performed, and the staining pattern was studied in all 78 cases. A detailed histopathological evaluation including subtyping was carried out for BCC cases. Results: All BCCs showed positivity with CD10 and BerEP4, but the intensity and pattern varied. Squamous cell carcinomas were completely negative for BerEP4 and CD10 in tumour cells, and 25 of 34 cases showed stromal CD10 positivity. Among adnexal tumours of follicular differentiation, proliferating trichilemmal tumour was completely negative for both markers; other adnexal tumours (n = 11/16) showed peritumoral stromal accentuation for CD10, and nine of 11 cases showed BerEP4 tumour cell positivity (P < 0.001). Conclusion: BerEP4 can reliably detect BCCs of all types and distinguish between BCC and SqCC, but it is unable to do so for adnexal tumours such as trichoepithelioma, trichilemmoma and trichoblastoma. CD10 is a useful adjunct marker in distinguishing both trichoepithelioma (TE) and SqCC from BCC. CD10-positive tumour cells favour a diagnosis of BCC and peritumoral stromal accentuation for trichoblastoma (TB) and trichilemmoma (TL). Tumour cells in SqCC are almost always negative for CD10. A combined immunohistochemistry (IHC) panel of CD10 and BerEP4 can serve as a very reliable adjunctive in the diagnosis of BCC.

A Rare Case of Verrucous Carcinoma and Trichoblastoma of the Neck: A Case Report and Literature Review.

Verrucous carcinoma (VC) is a variant of cutaneous squamous cell carcinoma. This phenomenon mainly affects the oropharynx, genitalia, and soles of the feet. VC is a well-defined, exophytic, cauliflower-like growth that is warty in nature. Trichoblastoma is a benign epithelial tumor composed of follicular germinative cells. It presents as a small, smooth, non-ulcerated, skin-colored nodule on the scalp, neck, thigh, and perianal regions. The dual presentation of verrucous carcinoma and trichoblastoma of the neck is rare. Though treatment can be achieved through surgical resection, early detection offers a good prognosis. We present the case of a 54-year-old homeless male who presented with an unusual neck mass that was initially misidentified as an abscess. Surgical debridement was performed, and histopathological analysis revealed the presence of a rare combination of VC and trichoblastoma. This report highlights the challenges of this rare presentation, which may be overlooked or misdiagnosed as an abscess.

Trichoblastic carcinosarcoma of the neck: Case report and molecular analysis of a seldom, relapsing entity and a review of the literature.

Trichoblastic carcinosarcoma is a seldom biphasic adnexal tumor with malignant epithelial and mesenchymal components. The authors report the first tumor on the neck developed from preexistent trichoblastoma showing aggressive, recurrent behavior. An 82-year-old man presented with a solitary 3-cm exophytic lesion. Histology verified the diagnosis of trichoblastic carcinosarcoma. Four years earlier, a trichoblastic carcinoma arising in a preexisting trichoblastoma was excised at the same location. Despite successful surgical treatments, three local recurrences within 4 years were diagnosed. After the second relapse, the patient agreed on adjuvant radiation. Twelve months later, another relapse was excised in toto. In the last surgical specimen, only the mesenchymal component was found. Copy number variation analysis of the preexisting tumor and two recurrences revealed the same entity and additional chromosomal aberrations in the recurrences. Adnexal carcinosarcomas are seldom, yet presumably underdiagnosed biphasic tumors with aggressive growth potential. They should have adequate preoperative clarification with wide tumor excision, as radiosensitivity seems to be of limited effect.

Hedgehog pathway mutations are involved in the pathogenesis of plaque-type "trichoblastoma": A report of two cases.

We present two cases of plaque-type trichoblastoma with atypical foci. A rare variant of trichoblastoma is the plaque variant, which is characterized by poor circumscription and locally infiltrative growth pattern. These lesions mostly require multiple stages of Mohs micrographic surgery. Debate still exists whether this variant should be considered as a benign entity or as "low-grade" malignant counterpart of trichoblastoma. In this report we describe two cases of plaque-type trichoblastoma with atypical foci, which harbored somatic mutations in the Hedgehog pathway, thus should be acknowledged as intermediate malignancies. In addition, extensive molecular workup of both the trichoblastic and atypical component in sequential lesions in the same patient was performed.

A case of racemiform trichoblastoma in a dog.

Trichoblastoma, which is common in dogs, is now occurring with other cellular changes outside the recognized forms to warrant their continuous evaluation for proper elucidation even as their causes largely remain unknown. A case at hand involved a 9-year-old Caucasian dog, which weighed 35 kg with chief complaint of a progressive bleeding mass on the scalp. The dog had an up-to-date vaccination record and all vital parameters were within optimum ranges. The surgical excision of the firm, solitary, and alopecic mass with traumatized upper surface revealed the presence of a well-demarcated and unencapsulated mass composed of grapes-like nests of basaloid epithelial cells within follicular stroma devoid of stromal necrosis, inflammatory cellular infiltration, and neoplastic epidermal connection. However, there was tissue necrosis, hemorrhages, and inflammatory cellular infiltrates on the exposed upper part of the traumatized growth. Immunohistochemical analysis showed positive reactivity to AE1/AE3, CK5/6, and p63 but negative immunoreactivity to CK7, CK20, CEA, and TTF-1. The histomorphological and immunohistochemical evaluation of the mass on the scalp of the dog suggested a solitary racemiform trichoblastoma with a traumatized exposed upper part despite basal cell carcinoma mimicry where histological diagnosis currently hold sway over immunohistochemical evaluation.

Malignant Trichoblastoma with Sarcomatous Stroma in a Rabbit.

A 10-year-old female rabbit developed an unencapsulated and asymmetrical superficial dermal mass on the neck. The tumour was invasive with central ulceration and contained three different histological components, namely trichoblastomatous, basal cell carcinoma (BCC)-like and undifferentiated carcinomatous. In the trichoblastomatous component, which occupied most of the tumour, epithelial neoplastic cells formed ribbon-like cellular trabeculae with a palisaded appearance and stromal giant cells. The BCC-like component was a unique lesion composed of epithelial foci and sarcomatous stroma. The sarcomatous stroma consisted of pleomorphic mesenchymal cells with collagen fibres and frequent giant cells with one or more bizarre nuclei. In the undifferentiated carcinomatous component, neoplastic cells had a sheet-like growth pattern without trichoblastic or squamous differentiation. Immunohistochemically, neoplastic epithelial cells were positive for p63 and cytokeratin (CK) while the stromal and giant cells were immunopositive for vimentin but negative for CK and p63. This is the first report of a malignant trichoblastoma with a sarcomatous stroma in animals.

Periocular Trichoblastoma: A Diagnostic Dilemma.

A 41-year-old woman presented with a large medial canthal lesion that extended over the midline. Excisional biopsy revealed a multinodular basaloid tumor, located within the dermis and subcutaneous fat that extended into skeletal muscle at the deep and peripheral margin. Histology was consistent with trichoblastoma. A review of the literature reveals a lack of specific and sensitive immunohistochemistry markers to establish the diagnosis of trichoblastoma. Following reconstruction, the patient has shown no signs of recurrence of the lesion at 24 months.

Cutaneous lymphadenoma in a young Saudi female: a case report.

Background: Cutaneous lymphadenoma (CL) is a rare benign epithelial neoplasm. It presents as skin-colored nodule in the head and neck area. CL is an uncommon condition with less than 60 cases reported in the literature and very rare occurrence in the Asian population; it has never been previously reported in the Arabian gulf countries. We report the first case of CL in a young Saudi female. Case Description: A 28-year-old Saudi female presented with an asymptomatic skin lesion on her forehead that first appeared eight years ago. Physical examination showed a 3 mm × 3.4 mm solitary, nontender, firm, skin-colored to pink nodule with overlying telangiectasia. A biopsy was taken, and histopathology findings revealed epithelial nests of uniform, small basaloid cells with some peripheral palisading; a fibrotic stroma; and Lympho-histiocytic inflammatory infiltrates. No retraction artifacts, atypia or necrosis were observed. These findings are consistent with CL. The lesion was fully excised by skin punch biopsy without any residual tumor. No recurrence was observed after 1 year follow-up. Conclusions: CL presents a diagnostic pitfall, and many dermatologists fail to recognize it in the initial clinical impression. Moreover, although CL is a rare and benign tumor, it must be in the differential diagnosis of any asymptomatic skin nodule in the head and neck area.

Significance of Dermoscopy in Association with Clinical Features in Differentiation of Basal Cell Carcinoma and Benign Trichoblastic Tumours.

Background: Although basal cell carcinoma (BCC) can, in the majority of cases, be diagnosed based on clinical and dermoscopic assessment, a potential overlap with benign adnexal skin tumours seems to exist, including trichoblastic tumours (TT). Methods: Retrospective analysis of clinical and dermoscopic features of benign TT and BCC cases was performed to develop a diagnostic algorithm with a potential utility in clinical practice. Results: In the study, 502 histopathologically confirmed BCC cases were compared with 61 TT (including 44 TB (72.13%), 10 TE (16.39%) and 7 DTE (11.48%]). Patients in the BCC group were statistically older (mean age was 71.4 vs. 64.4 years, respectively; p = 0.009). BCC presented generally as larger tumours (mean tumour size 11.0 vs. 8.2 mm for the TT group; p = 0.001) and was more frequently associated with clinically visible ulceration (59.4% vs. 19.7%, respectively; p < 0.001). Comparison of lesion morphology, clinically visible pigmentation, and anatomical location did not show significant differences between the analysed groups. Dermoscopically visible ulceration was significantly more common in the BCC group compared to the TT group (52.2% vs. 14.8%; p < 0.0001). Pigmented structures, specifically brown dots and brown globules, were significantly more prevalent in the TT group (32.8% vs. 11.4%; p = 0.0001 and 29.5% vs. 8.2%; p <0.0001). Similarly, TT more commonly than BCC showed the presence of cloudy/starry milia-like cysts (26.2% vs. 11.6%; p = 0.0031) and yellow globules (16.4% vs. 7.2%; p = 0.033). Conclusions: Despite differences in frequency of clinical and dermoscopic features between BCC and TT in the studied group, differential diagnosis based on these variables is not reliable. Histopathological examination remains a diagnostic gold standard in differentiation of BCC and TT.

Recurrent FOXK1::GRHL and GPS2::GRHL fusions in trichogerminoma.

We report 21 cases of trichogerminoma harbouring previously undescribed FOXK1::GRHL1/2 or GPS2::GRHL1/2/3 in-frame fusion transcripts. Microscopic examination of a preliminary set of five cases revealed well-delimitated tumours located in the dermis with frequent extension to the subcutaneous tissue. Tumours presented a massive and nodular architecture and consisted of a proliferation of basaloid cells. A biphasic pattern sometime resulting in tumour cell nests ('cell balls') was present. Immunohistochemistry demonstrated the expression of cytokeratins (CKs) 15, 17, and PHLDA1. In addition, numerous CK20-positive Merkel cells were detected. RNA sequencing (RNA-seq) revealed a FOXK1::GRHL1 chimeric transcript in three cases and a FOXK1::GRHL2 fusion in two cases. In a second series for validation (n = 88), FOXK1::GRHL1/2 fusion transcripts were detected by RT-qPCR or FISH in an additional 12 trichogerminomas and not in any other follicular tumour entities or basal cell carcinoma cases (n = 66). Additional RNA-seq analysis in trichogerminoma cases without detected FOXK1::GRHL1/2 rearrangements revealed GPS2::GRHL1 fusion transcripts in two cases, GPS2::GRHL2 in one case, and GPS2::GRHL3 fusion transcript in one case. Therefore, our study strongly suggests that GRHL1/2/3 gene rearrangements might represent the oncogenic driver in trichogerminoma, a subset of follicular tumours characterized by immature features and numerous Merkel cells. © 2022 The Pathological Society of Great Britain and Ireland.

Trichoblastic carcinoma: a comprehensive review of the literature.

Trichoblastic carcinoma is a rare neoplasm thought to arise from malignant degeneration of benign follicular tumors. Its clinical features, optimal treatment, and outcomes remain largely unknown. We performed a comprehensive review of the existing trichoblastic carcinoma literature. PubMed and Google Scholar were searched for keywords related to trichoblastic carcinoma, and additional articles were found in reference lists. Cases with a histopathologic diagnosis of trichoblastic carcinoma were summarized. A total of 93 cases have been described, all in case reports or case series. The average age was 65, with 66.7% of cases in males. A minority of patients had familial tumor syndromes or a history of radiation at the site, and only one was reported to be immunosuppressed. The most common site was the face (48.4%), and the majority developed de novo (87.1%). The clinical presentation was highly variable. Although most cases (82.8%) were successfully treated with surgery alone, a subset of patients had more aggressive disease including local progression or recurrence in five cases, nodal metastases in five cases, and distant metastases in three cases. Trichoblastic carcinoma is a rare malignancy with the potential for aggressive behavior. Further research is needed to better characterize this neoplasm.