Kaposi Sarcoma Associated with Tofacitinib Use in a Patient with Rheumatoid Arthritis.

Kaposi sarcoma is a rare vascular malignancy associated with HHV-8 infection. Four variants of Kaposi sarcoma have been described: Classic, African, HIV-associated, and iatrogenic. Iatrogenic Kaposi sarcoma is typically associated with immunosuppression and organ transplantation. We present a case of iatrogenic Kaposi sarcoma associated with tofacitinib therapy. A 69-year-old woman with rheumatoid arthritis receiving tofacitinib presented with multiple firm, purple-red nodules and brown plaques on the left lower extremity and a single lesion on the right medial calf. Clinicopathologic correlation confirmed a diagnosis of Kaposi sarcoma. Tofacitinib was discontinued and she was started on Alitretinoin 0.1% gel bid. The purple-red Kaposi sarcoma nodules decreased 50% in size after 4 months and resolved at 1 year off the tofacitinib and initiation of alitretinoin gel. As the use of immunomodulators and biologics continues to expand, awareness of this association is important for prompt diagnosis and management.

Cutaneous Sporothrix globosa infection mimicking cryptococcosis in a patient with history of kidney transplant.

Sporotrichosis is a subacute-to-chronic infection caused by Sporothrix species, a dimorphic fungus. Virulence varies by Sporothrix species and presentation can be region dependent. The patient had a history of immunosuppression as a result of a kidney transplant, and presented with a high disease burden on histopathological examination, but responded well to itraconazole. The case suggests considering Sporothrix speciation in immunocompromised patients to best determine treatment modality and duration.

Localized lymphomatoid papulosis: Unilesional lymphomatoid papulosis, regional lymphomatoid papulosis, and persistent agmination of lymphomatoid papulosis.

Lymphomatoid papulosis (LYP), the most common primary cutaneous CD30-positive lymphoproliferative disorder, is heralded by multiple papular and nodular lesions at anatomically discontiguous cutaneous sites. The histologic patterns are protean. An uncommon form of LYP is one that is anatomically confined. Cases of unilesional LYP, regional LYP, and persistent agmination of LYP were encountered in the routine and consultative practices of Weill Cornell Medicine, Division of Dermatopathology. The clinical presentation, outcomes, light microscopic findings, and phenotypic profile are reviewed. There were 10 cases of LYP presenting as solitary plaques or nodules primarily occurring in older patients and without a relevant medical history in most. Most cases occurred at an acral site with many localized to the foot; the morphology was one of a necrotizing angiocentric type E pattern and borderline type C morphology. Two of the unilesional patients in our series went on to develop mycosis fungoides, one at the initial site of unilesional type A LYP, and the other at a discontiguous site. Excluding one case, the solitary lesions underwent complete regression; after the lesions regressed, some cases had no apparent recurrence. The second anatomically confined variant of LYP in our series was regional LYP exhibiting a type E morphology in two cases and a hybrid type A and granulomatous eccrinotropic morphology in one case. There was no subsequent development of lymphoma, nor was there any spread to additional anatomic sites. The final category was persistent agmination of LYP, whereby the agminated papules of LYP were superimposed on a plaque of cutaneous T-cell lymphoma represented by mycosis fungoides in two and follicular helper T-cell lymphoma in one. In conclusion, anatomically confined LYP defines an uncommon form of LYP, but it is an important one to recognize because the histology can be worrisome despite an indolent clinical course. The clinical presentation, the infrequent association with lymphoma/leukemia, and histology are similar to conventional LYP, although there appears to be a greater tendency for complete regression without recurrence, excluding cases of persistent agmination of LYP whereby the clinical course warrants categorization as a form of cutaneous T cell lymphoma (CTCL).

Two cases of congenital dermatomyofibroma.

We present two infants with histologically confirmed congenital dermatomyofibromas. Congenital cases are rare with only one prior case reporting presence since birth. Given the benign nature of the lesions and propensity of dermatomyofibromas to resolve without intervention in young male patients, no additional treatments were pursued.

Clear Cell Differentiation in Eccrine Porocarcinoma as a High-Risk Feature: Epidemiologic and Pathologic Features of Eccrine Porocarcinoma in a Single-Center Case Series.

ABSTRACT: Eccrine porocarcinoma (EPC) is a rare sweat gland malignancy. Recognition of histologic features is challenging, and specific pathologic features correlate with risk of poor outcome. This single-center retrospective review and case series of 58 EPC cases from 2000 to 2016 elucidates epidemiologic and pathologic characteristics of EPC. Pathology slides from 52 cases were analyzed by a dermatopathologist for standardized variable characteristics, including previously determined high-risk features (HRF) associated with poor prognosis. The incidence of EPC increased over the study period with 3 times more cases diagnosed in the last 4 years than in the first 4 years. Most cases were in the elderly males (mean age 75 years), and 50% were located in the head and neck region. Although 38% of tumors exhibited one histologic HRF, only 10% exhibited more than one. Of the HRF, a greater tumor depth was associated with both increased age (P = 0.04) and clear cell differentiation (P = 0.02). This study elucidates epidemiologic and pathologic features of EPC and highlights how age and clear cell differentiation can be associated with greater tumor depth, although further research is needed to determine whether clear cell differentiation is associated with poor clinical outcome.

Signet-ring squamous cell carcinoma: a report of a rare variant and review of the literature.

Signet-ring squamous cell carcinoma is a rare histological subtype of squamous cell carcinoma. The distinct morphologic appearance of this variant can mimic metastatic adenocarcinoma and impose a diagnostic challenge. Unlike its glandular counterpart, signet-ring cell variant of squamous cell carcinoma has a poorly characterized histopathogenesis with no known prognostic implication. We describe an additional case and review the literature.

A Rare Perineurioma/Granular Cell Tumor Hybrid Peripheral Nerve Sheath Tumor.

Hybrid peripheral nerve sheath tumors (PNSTs) are rare benign composite neoplasms demonstrating features of multiple endogenous nerve sheath cell types. Hybrid PNSTs with granular cell components are exceedingly rare. Only a handful number of hybrid PNSTs composed of granular cell tumor and perineurioma have been described to date. We present a rare hybrid of perineurioma and granular cell tumor and review the literature.

A histo-immunopathologic and prognostic study of erythrodermic cutaneous T-cell lymphoma.

BACKGROUND: Sézary syndrome (SS) and erythrodermic mycosis fungoides (E-MF) represent two expressions of erythrodermic cutaneous T-cell lymphoma (E-CTCL). METHODS: Histopathologic features were compared on skin specimens from 41 patients with SS and 70 patients with E-MF. Immunopathologic findings were compared on 42 SS and 79 E-MF specimens. RESULTS: Specimens of SS usually showed band-like dermal infiltrates with intermediate-sized lymphoid cells and few plasma cells; on the other hand E-MF more often had a perivascular infiltrative pattern, predominance of small/mixed lymphoid cells and eosinophils. SS also had lower numbers of CD8+ cells and higher numbers of CD62L+ cells compared to E-MF. For E-MF patients, the presence of large Pautrier collections, infiltrates with intermediate-sized cells, increased number of mitotic figures and ≥50% CD62L+ cells in the dermal infiltrate correlated with a relatively poor disease-specific survival. However, only the presence of mitotic figures retained prognostic significance with clinical stage as a covariate. CONCLUSIONS: Clinical stage provides the most important prognostic information for patients with E-CTCL. However, mitotic activity for E-MF and CD8+ cells <20% for SS have additional value. We hypothesize that observed differences in plasma cell and eosinophil numbers may reflect the influence of CD62L+ central memory T-cells in the microenvironment.

Unilesional Follicular Mycosis Fungoides: Report of 6 Cases and Review of the Literature.

Unilesional follicular mycosis fungoides (MF) is a rare variant of cutaneous T-cell lymphoma characterized by selective involvement of the hair follicles by neoplastic T lymphocytes presenting initially as a solitary lesion occupying less than 5% of the body surface; there are 22 previous reported cases. We describe 6 patients with this rare variant of MF, all males (age range 6-64 years; mean age: 28 years) presenting with a solitary lesion primarily on the face and scalp except 1 patient who presented with a truncal lesion. All the patients had the lesions for at least a few months. The lesions were associated with follicular prominence and hair loss. In each, the biopsies showed an atypical folliculotropic lymphocytic infiltrate accompanied by follicular mucinosis in certain cases. The infiltrate involved the lower isthmic part of the follicle, and in 1 case, there was an alopecia areata-like neoplastic lymphomatoid bulbitis. There was no evidence of large cell transformation nor was there a significant degree of infiltration of the interfollicular dermis or epidermis. Higher magnification disclosed marked cerebriform atypia amidst the lymphocytes. Phenotypic studies demonstrated a high CD4 to CD8 ratio in excess of 5 with a significant loss of CD7. One patient developed additional similar lesions involving the thigh and buttock after a period of at least 3-4 years of untreated unilesional MF. Unilesional follicular MF is a potentially curable form of MF with a young male predilection. Early diagnosis and treatment intervention likely define a cornerstone for ensuring the best patient outcome and preventing clinical evolution to either tumor stage MF and or multilesional MF.

Trichophytum rubrum endonyx onychomycosis resistant to standard oral and topical therapies.

We present a 45 year-old man with an eight-year history of discoloration of the nail plate on his left hallux. He had been treated with two courses of oral terbinafine and topical 8% ciclopirox for presumed onychomycosis. On exam, his left great toenail contained a wide yellow-white longitudinal band involving a majority of the nail plate. No subungual debris, hyperkeratosis, or paronychial inflammation was present in the affected nail. Histopathology of the nail plate revealed numerous fungal elements arranged transversely and longitudinally, solely within the keratin layers of the nail plate; these were highlighted with periodic acid-Schiff (PAS) stain confirming endonyx onychomycosis. Cultures grew Trichophyton rubrum. All types of onychomycosis under the new classification system proposed by Hay et al. have now been associated with T. rubrum. Endonyx related to T. rubrum may be a particularly difficult infection to treat with oral or topical agents owing to the absence of robust local immune response and limited drug penetration to the interior nail plate. Physicians should be aware that this type of infection may require treatment with dual-agent therapy or alternative modalities including chemical or surgical plate avulsion or photodynamic therapy.

Dermal eosinophilic infiltrate in junctional epidermolysis bullosa.

Junctional epidermolysis bullosa (JEB) is a rare genodermatosis characterized by a split in the lamina lucida usually because of mutations in LAMA3, LAMB3 and LAMC2 resulting in absence or reduction of laminin-332. Rare subtypes of JEB have mutations in COL17A1, ITGB4, ITGA6 and ITGA3 leading to reduction or dysfunction of collagen XVII, integrin α6ß4 and integrin α3. The classic finding under light microscopy is a paucicellular, subepidermal split. We describe the unusual presence of an eosinophilic infiltrate in the bullae and subjacent dermis in a neonate with JEB, generalized intermediate (formerly known as non-Herlitz-type JEB), discuss the histologic differential diagnosis for a subepidermal blister in a neonate, review the literature regarding cases of epidermolysis bullosa (EB) presenting with inflammatory infiltrates, and discuss mechanisms to explain these findings. This case highlights that eosinophils can rarely be seen in EB and should not mislead the dermatopathologist into diagnosing an autoimmune blistering disorder.

Superficial acral fibromyxoma and other slow-growing tumors in acral areas.

Superficial acral fibromyxoma (SAFM) is a rare fibromyxoid mesenchymal tumor with a predilection for the distal extremities and frequent nail bed involvement. Superficial acral fibromyxoma typically arises as a solitary, slow-growing nodule on a toe or finger, with the great toe being the most commonly affected site. Histopathologically, SAFM characteristically presents as a well-circumscribed but unencapsulated dermal tumor composed of spindle and stellate cells in a loose storiform or fascicular arrangement embedded in a myxoid, myxocollagenous, or collagenous stroma. The tumor often occupies the entire dermis and may extend into the subcutis and occasionally the underlying fascia and bone. The characteristic immunohistochemical profile of SAFM includes expression of CD34, epithelial membrane antigen (EMA), and CD99; it is notably negative for S-100 protein. We report 3 cases of SAFM and also provide a review of the literature on the clinical and histopathologic presentations of this unique entity as well as the differential diagnosis.