A case of malignant proliferating trichilemmoma of the scalp with multiple metastases

Adnexal neoplasms of the eye

Adnexal neoplasms of the eyelid encompass a wide variety of benign and malignant tumors of sebaceous, follicular, and sweat gland origin. Due to the specialized structures of the eyelid, these neoplasms present differently when compared with those of other locations. Although most dermatologists and ophthalmologists are familiar with the commonly reported adnexal tumors of the eyelid, such as hidrocystoma, pilomatrixoma, and sebaceous carcinoma, many other adnexal neoplasms have been reported at this unique anatomic site. Accurate and timely identification of these neoplasms is essential, as alterations of eyelid anatomy and function can have a negative impact on eye health, vision, and quality of life. We review the clinical and histopathologic features of common and rare eyelid adnexal neoplasms and discuss proposed treatment options.

Malignant Proliferating Pilar Tumor: Clinicopathologic, Immunohistochemical, and Molecular Study of 17 Cases

Proliferating pilar tumors are rare neoplasms that differentiate toward the outer sheath near the isthmus and can rarely undergo malignant transformation. We performed histopathologic evaluation on 26 benign proliferating pilar tumor (BPPT) and 17 malignant proliferating pilar tumor (MPPT). Ki-67 and p53 immunostains were performed on 13 BPPT and 10 MPPT. Six MPPT cases were successfully analyzed by a next-generation sequencing platform which surveyed exonic DNA sequences of 447 cancer genes and 191 regions across 60 genes for rearrangement detection. Patient demographics and clinical characteristics were similar between the BPPT and MPPT groups. Follow-up data of 16 of 17 MPPT (median, 25 mo) showed metastasis in 1 MPPT. The histologic features associated with MPPT include size >2.5 cm, adjacent desmoplastic stroma, small nests or cords of atypical epithelium in surrounding stroma, irregular infiltration or borders, abnormal keratinization, large hyperchromatic nuclei, prominent nucleoli, severe cytologic atypia, nuclear pleomorphism, necrosis, and increased mitotic figures. MPPT harbors copy number gains of 15q and losses of 6p and 6q, findings previously reported in BPPT. However, MPPT harbors frequent TP53 mutations as molecular markers of progression. Different from cutaneous squamous cell carcinoma, MPPT more frequently demonstrates low tumor mutational burden and typically lacks a UV signature, suggestive of a different etiologic pathway than squamous cell carcinoma. In summary, with a median follow-up of 25 months, this study shows that MPPT is a biologically indolent carcinoma with rare metastasis. Molecular analyses suggest a non-UV-related pathogenesis with frequent TP53 aberration.

Malignant Proliferating Trichilemmal Tumor of the Scalp: A Systematic Review

OBJECTIVES

Malignant proliferating trichilemmal tumors of the scalp can exhibit aggressive presentation and recurrences. Our objective was to perform an evidence-based systematic review evaluating clinical presentation, tumor characteristics, and treatment modalities used to determine which treatment strategies had the best outcomes.

METHODS

The databases PubMed, Embase, and Cochrane Library were searched for relevant literature by the authors. Patient demographics, imaging, treatments, and other clinical characteristics were obtained. The results were reported using the Preferred Reporting Systems for Systematic Reviews and Meta-Analysis guidelines.

RESULTS

Thirty-nine studies with a total of 65 patients were identified. The most common presentation was a history of slow-growing, painless swollen mass on the scalp. In total, 10 patients (15.4%) presented with spread to the regional lymph nodes and 6 (9.2%) additional patients presented with metastasis to distant locations. In total, 61 patients (93.8%) underwent surgery. Various chemotherapy and radiation therapy regimens were used. Of the 45 cases with documented follow-up, 11 (24.4%) patients had one or multiple instances of local, lymph node or metastatic tumor recurrence.

CONCLUSIONS

Surgery is favored, and the exact approach should be based on clinical judgment. However, Mohs micrographic surgery should strongly be considered because of its superior margin control against such an invasive tumor. Radiotherapy and chemotherapy have been used as adjuvant therapy in aggressive cases or recurrence. Patients should be followed closely and examined often to frequently assess recurrence or metastasis. Randomized controlled trials are needed to further clarify these findings.

Scalp malignant trichilemmal tumour with bony erosion: a new clinical entity

Trichilemmoma is a benign tumour which arises from the hair follicle root sheath, and commonly occurs in the head and neck area. Malignant transformation and locally aggressive growth of these tumours are very rare. Surgical excision remains the mainstay of management, with scarce evidence for other treatment modalities. We describe our experience of a malignant trichilemmal tumour which demonstrated bony erosion with intracranial extension. Our patient was treated with radical radiotherapy, with a good response at 6 months of follow-up. This case highlights the need to consider malignant potential in recurrent skin lesions, along with the potential for trichilemmoma to erode bone, necessitating the consideration of different treatment modalities.

Genomic landscape of a metastatic malignant proliferating tricholemmal tumor and its response to PI3K inhibition

Proliferating tricholemmal tumors (PTTs) are rare benign neoplasms that arise from the outer sheath of a hair follicle. Occasionally, these PTTs undergo malignant transformation to become malignant proliferating tricholemmal tumors (MPTTs). Little is known about the molecular alterations, malignant progression, and management of MPTTs. Here, we describe the case of a 58-year-old female that had a widely metastatic MPTT that harbored an activating PIK3CA mutation and was sensitive to the PI3K inhibitor, alpelisib (BYL719). We review the available literature on metastatic MPTT, detail the patient's course, and present a whole genome analysis of this rare tumor.

Cellular microenvironment controls the nuclear architecture of breast epithelia through β1-integrin

Defects in nuclear architecture occur in a variety of diseases, however the fundamental mechanisms that control the internal structure of nuclei are poorly defined. Here we reveal that the cellular microenvironment has a profound influence on the global internal organization of nuclei in breast epithelia. A 3D microenvironment induces a prolonged but reversible form of cell cycle arrest that features many of the classical markers of cell senescence. This unique form of arrest is dependent on signaling from the external microenvironment through β1-integrins. It is concomitant with alterations in nuclear architecture that characterize the withdrawal from cell proliferation. Unexpectedly, following prolonged cell cycle arrest in 3D, the senescence-like state and associated reprogramming of nuclear architecture are freely reversible on altering the dimensionality of the cellular microenvironment. Breast epithelia can therefore maintain a proliferative plasticity that correlates with nuclear remodelling. However, the changes in nuclear architecture are cell lineage-specific and do not occur in fibroblasts, and moreover they are overcome in breast cancer cells.

Challenges in the diagnosis of cutaneous adnexal tumours

The diagnosis of cutaneous adnexal neoplasms, a heterogeneous group of entities, is often perceived by practising pathologists as challenging. A systematic approach to diagnosis is necessary for classification of these lesions, which establishes the tumour differentiation (follicular, sebaceous, sweat gland or apocrine) and evaluates histological features differentiating between benign and malignant entities. Consideration of clinical history is a necessary adjunct in evaluation of the adnexal neoplasm, as characteristic anatomical sites are described for many adnexal lesions. In some instances, immunohistochemical studies may also be employed to aid the diagnosis. The differential diagnosis between primary cutaneous adnexal neoplasms and cutaneous metastases from visceral tumours may also be difficult. Clinical, radiological, histological and immunohistochemical characteristics will be further discussed, considering that the correct diagnosis has a significant impact on the patient's management and prognosis.

Orbital malign trichilemmal tumor with cerebral involvement

Proliferating trichilemmal tumor is a rare encountered neoplasm. This neoplasm is usually benign, but it may be locally aggressive. To the best of our knowledge, magnetic resonance (MR) imaging features of cerebral involvement of this unusual neoplasm have not been described. We report the MR imaging findings of a case of malign proliferating trichilemmal tumor, with cerebral involvement.

Morphological spectrum of pilar cysts

Background:

Cysts of the skin are one of the commonly excised specimens in the surgical outpatient department. A majority of them being clinically diagnosed as sebaceous cysts, their true nature is only discernible on histopathological examination. Closer examination of the type of keratinization involved will throw light into the exact nature of the cyst. Trichilemmal or Pilar cyst is one such entity, which presents in both a non-neoplastic and neoplastic form.

Aims:

The present retrospective observational study was undertaken to find out the incidence of these cysts in surgical pathology practice in a rural hospital and to enlist the various morphological forms that these cysts may take.

Materials and Methods:

The histopathology files were reviewed for a period of 6 years for cases coded as pilar cyst.

Results:

A total of eight cases (5.75%) were identified, which showed features of trichilemmal differentiation. A single case each of proliferating trichilemmal cyst and malignant proliferating trichilemmal tumors were noted. Most of the cases were seen among females on the scalp.

Conclusions:

Trichilemmal tumor is an uncommon histopathological entity. Many of these lesions may be mistakenly diagnosed due to lack of recognition of the unique type of keratinization.

MR Imaging Findings of Giant Trichilemmal Carcinoma on the Scalp. A Case Report

We describe the magnetic resonance imaging findings of a huge trichilemmal carcinoma (TLC) on the parietal and occipital region of the scalp in one patient. Our aim is to discuss the clinical, radiologic, and pathologic features of scalp TLC and to review relevant literature regarding this tumor. One patient with recent rapid tumor growth in the parietal and occipital region of the scalp underwent MR studies and subtotal resection. The tumor was seen as a poorly marginated and lobulated soft-tissue mass with isointense signal on T1-weighted images and hyperintense signal on T2-weighted images. Necrosis and ulceration were also found on the tumor surface. The TLC has been massively invading the nearby skull, meninges, brain tissue, and superior sagittal sinus. After exhibiting contrast, the tumor showed significant enhancement, with small portions remaining unenhanced. Subtotal excision of the mass and reconstruction of the scalp were performed. Microscopically, the mass was composed of trabecular growth of tumor cells with clear cytoplasm, prominent nucleoli, frequent mitoses, and foci of trichilemmal keratinization. Tumor on the scalp with heterogeneous, mixed signals on T2-weighted images, significant enhancement of solid portion, and local infiltration accompanied by surface deep ulceration may indicate a TLC. Wide surgical excision with tumor-free margins remains the best choice for treatment.

Malignant Proliferating Trichilemmal Tumor of the Lower Eyelid

PURPOSE

To report on the first case of malignant proliferating trichilemmal tumor (PTT) on the eyelid, and to describe the clinical and histopathologic findings.

METHODS

Interventional case report and literature review.

RESULTS

A 42-year-old woman presented with a 2-year history of a firm, 3 x 2 cm lower eyelid mass. The mass was excised with the frozen section control. The defect in the lower eyelid was reconstructed with modified Hughes tarsoconjunctival flap and skin graft from the left postauricular area. Histopathologic examination revealed the proliferation of outer hair sheath epithelium with multiple central areas of trichilemmal keratinization. The presence of marked cellular atypia and frequent mitoses indicated the malignant transformation.

CONCLUSIONS

Malignant PTT has not yet been reported on the eyelid. Malignant PTT should be included in the differential diagnosis for eyelid tumors.

Magnetic resonance imaging findings of proliferating trichilemmal tumor

We report the magnetic resonance (MR) imaging findings of proliferative trichilemmal tumor (PTT), a rare benign tumor of the scalp. MR imaging showed a well-margined mass with isointense signal on T(1)-weighted images and heterogeneous mixed intensity signal on T(2)-weighted images After i.v. administration of contrast material, the mass showed significant enhancement, with small portions remaining unenhanced. It was considered that these findings reflected the pathological characteristics of PTT, which consists of solid lobules and cystic cavities.

Proliferating trichilemmal tumor with a malignant spindle cell component

BACKGROUND

Proliferating trichilemmal tumors (PTTs) are uncommon exuberant growths of cells derived from the external root sheath. They tend to occur in older women, with a predilection for the scalp. Resection is usually curative. Spindle cell components arising within PTTs are exceedingly rare, with only three known cases previously reported. Of these three cases, one patient died from widespread metastasis.

METHODS

Histological and immunohistochemical examinations were performed on a tumor from a 54-year-old man which, after exhibiting slow growth for 3 years, increased rapidly in size.

RESULTS

Microscopic examination revealed cystic lobules of squamous cells without a granular cell layer surrounding amorphous eosinophilic debris within the dermis. Also present was a poorly circumscribed focus of spindle cells with hyperchromasia, pleomorphism, giant cells, and abundant mitoses, including abnormal forms. Immunohistochemistry showed the spindle cells to stain positively for vimentin, but negatively for keratin, epithelial membrane antigen and S-100 antibodies.

CONCLUSION

A malignant spindle cell component arising within a PTT is a rare neoplasm which has been associated with death from widespread metastasis.