Malignant eccrine poroma with multiple visceral metastases: report of a case with autopsy findings

Heterogeneity of PD-L1 expression and CD8 tumor-infiltrating lymphocytes among subtypes of cutaneous adnexal carcinomas

BACKGROUND

Adnexal carcinomas are rare and heterogeneous skin tumors, for which no standard treatments exist for locally advanced or metastatic tumors.

AIM OF THE STUDY

To evaluate the expression of PD-L1 and CD8 in adnexal carcinomas, and to study the association between PD-L1 expression, intra-tumoral T cell CD8+ infiltrate, and metastatic evolution.

MATERIALS AND METHODS

Eighty-three adnexal carcinomas were included. Immunohistochemistry using anti-PD-L1 monoclonal antibodies (E1L3N and 22C3) and CD8 was performed. PD-L1 expression in tumor and immune cells, and CD8+ tumor-infiltrating lymphocyte (TIL) density were analyzed semi-quantitatively.

RESULTS

Among the 60 sweat gland, 18 sebaceous and 5 trichoblastic carcinomas, 11% expressed PD-L1 in ≥ 1% tumor cells, more frequently sweat gland carcinomas (13%, 8/60) including apocrine carcinoma (40%, 2/5) and invasive extramammary Paget disease (57%, 4/7). Immune cells expressed significantly more PD-L1 than tumor cells (p < 0.01). Dense CD8+ TILs were present in 60% trichoblastic, 43% sweat gland, and 39% sebaceous carcinomas. CD8+ TILs were associated with PD-L1 expression by tumor cells (p < 0.01). Thirteen patients out of 47 developed metastases (27%) with a median follow-up of 30.5 months (range 7-36). Expression of PD-L1 by tumor cells was associated with the development of metastasis in univariate analysis (HR 4.0, 95% CI 1.1-15, p = 0.0377) but not in multivariate analysis (HR 4.1, 95% CI 0.6-29, p = 0.15).

CONCLUSION

PD-L1 expression is highly heterogeneous among adnexal carcinoma subtypes, higher in apocrine carcinoma and invasive extramammary Paget disease, and associated with CD8+ TILs. Our data suggest the interest of evaluating anti-PD1 immunotherapy in advanced or metastatic cutaneous adnexal carcinoma.

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.

A case of eccrine porocarcinoma: usefulness of immunostain for s-100 protein in the diagnoses of recurrent and metastatic dedifferentiated lesions

Eccrine porocarcinoma is a rare malignant tumor. Immunostain for S-100 protein, in addition to epithelial membrane antigen (EMA) and carcinoembryonic antigen (CEA), is described to be useful in the diagnosis. Herein, we report a case of eccrine porocarcinoma with immunostain for S-100 protein which was useful in diagnoses of recurrent and metastatic lesions. The primary lesion in the left inguinal region was excised, but it recurred on the same site 14 months after the resection. The recurrent lesion showed epithelioid melanocytic findings. Three months later, metastasis to the lungs was found. Since these recurrent and metastatic lesions were dedifferentiated, typical histologic findings of eccrine porocarcinoma disappeared in biopsied specimens. Nevertheless, scattered immunoreactive cells for S-100 protein were maintained in these dedifferentiated lesions. S-100 protein positive cells could be an aid to diagnose, even if histologic findings of recurrent and metastatic lesions have changed by dedifferentiation.

Skin adnexal neoplasms--part 2: an approach to tumours of cutaneous sweat glands

Tumours of cutaneous sweat glands are uncommon, with a wide histological spectrum, complex classification and many different terms often used to describe the same tumour. Furthermore, many eccrine/apocrine lesions coexist within hamartomas or within lesions with composite/mixed differentiation. In addition to the eccrine and apocrine glands, two other skin sweat glands have recently been described: the apoeccrine and the mammary-like glands of the anogenital area. In this review (the second of two articles on skin adnexal neoplasms), common as well as important benign and malignant lesions of cutaneous sweat glands are described, and a summary for differentiating primary adnexal neoplasms from metastatic carcinoma is outlined, striving to maintain a common and acceptable terminology in this complex subject. Composite/mixed adnexal tumours are also discussed briefly.

Pigmented malignant hidroacanthoma simplex mimicking irritated seborrheic keratosis

Pigmented variant of malignant hidroacanthoma simplex (PMHS) is very rare. We are aware of only two reported cases, all arising in pigmented hidroacanthoma simplex (HS). We report the third case of PMHS arising in a pigmented HS. A 71-year-old-woman presented with a well-demarcated pigmented hyperkeratotic tumor on the right knee resembling irritated seborrheic keratosis. Histopathologic examination of the excised tumor revealed intraepidermal proliferation of atypical polygonal poroid cells forming large, sharply demarcated nests with colonization of dendritic melanocytes. In addition, there were focal changes of a benign pigmented HS and syringofibroadenoma. The key diagnostic features of ductal structures and intracytoplasmic lumina were highlighted by carcinoembryonic antigen and epithelial membrane antigen immunostaining. PMHS should be differentiated from irritated seborrheic keratosis, melanoacanthoma, Bowen's disease and malignant melanoma both clinically and pathologically.

Malignant eccrine poroma in an unusual location

Malignant eccrine poroma is a rare skin appendage tumour, originating from the intraepidermal and upper dermal eccrine ducts. The tumour either arises spontaneously or develops in a long-standing eccrine poroma, generally in elderly people over 60. Clinically, it tends to be a localized lesion, which manifests itself as a nodule or ulcerated tumour, favouring extremities. We report an 83-year-old female with an enlarging and bleeding tumour on her lumbosacral region. This lesion first appeared as a small pigmented papule and progressed to an erythematous patch with central papular portion and some peripheral pigmentation. Histopathology revealed malignant eccrine poroma. Also, immunohistochemically, diffuse and intense p53 staining was observed. Regular pigment pattern, brown globules and black dots were seen in dermoscopic examination. After performing a wide excision, 20 months of follow-up revealed no recurrence or metastasis of the tumour. This case represents an unusually located malignant eccrine poroma with some pigmentation.

Malignant eccrine poroma with spinal and cerebrospinal fluid metastases: case report

OBJECTIVE AND IMPORTANCE

A rare case of metastasizing malignant eccrine poroma (porocarcinoma) is described. This case is unique because metastasis resulted in hydrocephalus in the cerebrospinal fluid and spinal cord compression in the lumbar spine.

CLINICAL PRESENTATION

A 57-year-old man presented with acute confusion, lower limb weakness, and urinary concerns. Investigation revealed acute hydrocephalus and extradural cord compression of the lumbar spine.

INTERVENTION

The acute hydrocephalous was treated with a ventriculoperitoneal shunt. The spinal cord and conus were decompressed by laminectomy and supplemented with pedicular screw fixation.

CONCLUSION

The case reported here is the first with metastases from a malignant eccrine poroma causing spinal cord compression and acute hydrocephalus. Our observation is compared with a review of the literature.

Eccrine porocarcinoma (malignant eccrine poroma): a clinicopathologic study of 69 cases

The clinicopathologic characteristics of 69 cases of eccrine porocarcinoma (EP) have been studied. Seven cases of purely in situ disease are included. Forty patients were female, 29 male with ages ranging from 29 to 91 years (mean 73 years). The lower extremity represented the single most common site (44%). Other common sites were the trunk (15 cases, 24%) and head (11 cases, 18%). The histologic diagnosis of EP was predicated on the basis of an irregular tumor at least partly formed of characteristic poromatous basaloid epithelial cells displaying ductal differentiation, and significant cytologic atypia. Forty-seven tumors (68%) contained mature well-formed eccrine ducts having an eosinophilic luminal cuticle, with the remaining tumors containing small ill-formed ducts and/or intracytoplasmic lumina. All ducts were discernible via light microscopy and in 49 cases were highlighted with DPAS stain and/or CEA/EMA immunocytochemistry. A variant with a broad pushing tumor margin and marked nuclear pleomorphism showed some resemblance to proliferative bowenoid dysplasia. In 11 cases (18%) the tumors appeared to arise in continuity with a benign preexistent poroma. A variety of histologic patterns were displayed including clear, squamous, and spindle cell differentiation, mucus cell metaplasia, and colonization by melanocytes. Lymphovascular invasion was present in 9 cases (15%). Three cases showed pagetoid extension of malignant cells (epidermotropism) and appeared to be multifocal. Follow-up was available in 54 patients (78%) with 9 (17%) experiencing local recurrence, 10 developing lymph node metastases (19%), and 6 (11%) experiencing distant metastases or death. Mitoses, the presence of lymphovascular invasion, and tumor depth >7 mm were associated with a poorer prognosis. Dividing tumors into those with a "pushing" or "infiltrating" advancing margin was also predictive of outcome with the latter having an increased risk of local recurrence. This report, the largest series of EP to date, suggests that the incidence of aggressive behavior is less than popularly believed. Furthermore, EP can display a wide variety of histologic patterns that may lead to diagnostic error in the unwary. The large number of cases in this series enables a reliable evaluation of prognostic parameters. A more aggressive clinical course may be indicated by more than 14 mitoses per high power field (hazard ratio [HR] for death 17.0, 95% confidence interval [CI] 2.71-107), lymphovascular invasion by tumor (HR 4.41, CI 1.13-17.2), and depth >7 mm (HR 5.49, CI 1.0-30.3). Thus, mitoses, lymphovascular invasion, and tumor depth should be evaluated in these tumors. We also suggest that tumors presenting an "infiltrative" advancing margin are particularly prone to local recurrence and require wide excision with close attention to the surgical margins by the reporting pathologist.