Evan George

Basaloid squamous cell carcinoma of the head and neck. A clinicopathologic and immunohistochemical study of 40 cases.

In this study of 40 cases of basaloid squamous cell carcinoma, 83% arose in the pyriform sinus, base of tongue, tonsil, and larynx. The 35 men and five women ranged in age from 27 to 88 years (median 62). In patients for whom social habits were recorded, 24 of 26 patients were smokers and 22 of 25 drank ethanol. Most presented with stage III or IV disease. Twenty-seven patients had regional metastases at the time of presentation and 15 developed distant metastases. Seventeen patients died with disease (median survival 18 months). The tumors were composed of moderately pleomorphic basaloid cells forming nests, cords, and frequent cribriform patterns. Squamous dysplasia of surface mucosa, focal squamous differentiation within invasive basaloid squamous cell carcinoma, or foci of conventional squamous cell carcinoma were present, alone or in combination. All studied neoplasms were immunohistochemically positive for keratins with the 34(3E12 antibody. Approximately 80% were immunoreactive using AE1/AE3 or CAM 5.2. Epithelial membrane antigen, carcinoembryonic antigen, and SI00 protein were found in 83%, 53%, and 39%, respectively, of the cases. Diffuse, weak immunoreactivity for neuronspecific enolase was seen in 75% of tumors. Synaptophysin, chromogranin, muscle-specific actin, and glial fibrillary acidic protein were absent. Basaloid squamous cell carcinoma has been confused with adenoid cystic carcinoma and small cell undifferentiated carcinoma, but is usually distinguishable in routine hematoxylin and eosin- stained sections, or, in rare problematic cases, with the aid of immunohistochemical studies. Distinction is warranted because the biologic behavior of basaloid squamous cell carcinoma differs from that of both of these lesions.

Subclassification of desmoplastic melanoma: pure and mixed variants have significantly different capacities for lymph node metastasis

Background:  There is disagreement about the behavior and optimal management of desmoplastic melanoma (DM), particularly regarding the incidence of lymph node (LN) involvement. Recently, investigators have noted the frequently heterogenous histologic composition of DM and have found significant differences between pure desmoplastic melanoma (PDM) (≥90% comprised of histologically typical DM) and mixed desmoplastic melanoma (MDM) [≥10% DM and >10% conventional melanoma (CM)].

Immunohistochemical evaluation of p16INK4A, E-cadherin, and cyclin D1 expression in melanoma and Spitz tumors.

We evaluated the usefulness of immunohistochemical examination for E-cadherin, p16, and cyclin D1 in discriminating melanoma from Spitz tumors. Immunoperoxidase staining was performed on formalin-fixed tissue specimens from 46 Spitz tumors and 42 concurrent melanoma specimens. The percentages of immunoreactive melanocytes in the epidermis and dermis were estimated semiquantitatively. Qualitatively abnormal immunoreactivity patterns were also tabulated. Dermal p16 immunoreactivity was the best quantitative discriminator: decreased nuclear immunoreactivity (<25% of dermal melanocytes) was 3-fold more likely in melanoma than in Spitz tumors (P = .004). Loss of both nuclear and cytoplasmic dermal p16 immunoreactivity was 8-fold more likely in melanoma (P = .01). Qualitative irregularities in the zonal distribution of E-cadherin immunoreactivity were 2-fold higher in melanoma (P = .01), but these were often focal or subtle. There was no statistically significant difference in cyclin D1 immunoreactivity. In atypical Spitz tumors, the dermal p16 immunoreactivity and frequency of qualitative E-cadherin abnormalities were intermediate between those of ordinary Spitz nevi and melanoma. Also, contrasting immunoreactivity patterns were helpful in determining Breslow thickness in specimens containing melanoma and contiguous dermal nevi.

Malignant peripheral nerve sheath tumors of the skin.

We report two cases of cutaneous malignant peripheral nerve sheath tumors. One occurred in a patient without neurofibromatosis and manifested as a recurrent scalp nodule. Histologically, the lesion began as a benign-appearing, dermal neurofibroma and progressed to a highly cellular, pleomorphic neoplasm with prominent mitotic activity and invasion of the subcutis. Immunohistochemical and ultrastructural examination confirmed the nerve sheath origin of this tumor. The other case presented as a large scalp mass in a patient with an established diagnosis of neurofibromatosis; its immunohistochemical characteristics were identical to those of case 1. Although malignant peripheral nerve sheath tumors are uncommon in the skin, they can be effectively separated from other spindle cell neoplasms by specialized pathologic studies.

CD4+/CD56+ hematodermic neoplasm: report of a rare variant with a T-cell receptor gene rearrangement.

CD4+/CD56+ hematodermic neoplasm (HN), formerly known as a blastic natural killer (NK) cell lymphoma, is a rare subtype of a cutaneous dendritic cell neoplasm notable for highly aggressive behavior. The characteristic features are: expression of the T‐helper/inducer cell marker CD4 and the NK‐cell marker CD56 in the absence of other T cell or NK‐cell specific markers. In particular, CD3 (surface or cytoplasmic) and CD2 are not expressed. Although T‐cell receptor (TCR) genes are generally reported to be in a germline configuration, we present an unusual variant of a CD4+/CD56+ HN with a clonal rearrangement of TCR genes. This feature of a CD4+/CD56+ HN has been only rarely reported. Recognition of the presence of clonal TCR gene rearrangements in a small subset of CD4+/CD56+ HN is important to avoid misdiagnosis of this entity as an unusual variant of a cutaneous T‐cell lymphoma.

Scedosporium apiospermum: an emerging opportunistic pathogen that must be distinguished from Aspergillus and other hyalohyphomycetes.

We report a case of cutaneous Scedosporium apiospermum infection in an immunocompromised host. S.apiospermum is an emerging opportunistic pathogen, especially in organ transplant recipients. Prompt identification is critical because of its resistance to most antifungal drugs. Its histopathologic features are indistinct and overlap with those of more commonly recognized hyalohyphomycetes such as Aspergillus species. Cultures from infected tissue are generally required for correct identification. Clinicians and pathologists must be familiar with this organism and recognize the need for culture studies in addition to histopathology in the evaluation of specimens from immunocompromised patients with suspected fungal infection.

Cutaneous Mycobacterial Spindle Cell Pseudotumor: A Potential Mimic of Soft Tissue Neoplasms

A 55-year-old man with scleroderma treated with prednisone and etanercept presented with enlarging sporotrichoid nodules on the forearm. Microscopically, there were large circumscribed dermal and subcutaneous nodules of spindled and epithelioid cells, resembling a spindle cell neoplasm. Small foci of neutrophils were also present, and a subsequent Ziehl-Neelsen stain highlighted beaded acid-fast bacilli in the interstitium. Tissue culture demonstrated Mycobacterium chelonae. Cutaneous mycobacterial spindle cell pseudotumor is an exceedingly rare lesion, with only 6 previously reported cases. Although these included patients with autoimmune disease receiving immunosuppressive therapy, this is the first case reported in association with a tumor necrosis factor alpha inhibitor, etanercept. Furthermore, this represents the first mycobacterial spindle cell pseudotumor described in association with M. chelonae. Mycobacterial spindle cell pseudotumor should be considered in the differential diagnosis of cutaneous spindle cell proliferations, especially in immunocompromised patients.

Severe Drug Hypersensitivity Reaction in a Young Woman Treated with Doxycycline

Doxycycline is a commonly prescribed medication for the management of acne vulgaris. Severe adverse reactions to this medication are uncommon. We describe an unusual case of a 20-year-old female who experienced a life-threatening hypersensitivity reaction, including fever, lymphadenopathy, hepatitis, nephritis and severe pneumonitis with respiratory failure following oral administration of doxycycline for facial acne.

A rare case of plasmacytoma-like post-transplant lymphoproliferative disorder presenting in the skin of a lung transplant patient.

Post‐transplant lymphoproliferative disorder (PTLD) is a lymphoid proliferation that develops as a complication of solid organ or bone marrow transplants. Most cases usually present in the gastrointestinal tract, liver, kidney or lymph nodes. Plasmacytoma‐like PTLD is an uncommon variant, and presentation in the skin is exceedingly rare. We present a case of plasmacytoma‐like PTLD presenting as a leg mass in a 58‐year‐old male. Biopsy from the lesion exhibited atypical plasmacytoid and plasmablastic cells that showed lambda light chain restriction and stained positive for CD138 and Epstain‐Bar virus early RNA by in situ hybridization. These findings were diagnostic of plasmacytoma‐like PTLD. Only a few similar cases have been reported in the literature. The majority of these cases occurred in heart and kidney transplant patients. To our knowledge, this is the first reported case to occur in a lung transplant patient.

Oculocutaneous oncocytic tumors: clinicopathologic and immunohistochemical study of 2 cases with literature review.

Oculocutaneous oncocytic tumors (OCOTs) are uncommon neoplasms that have been reported only rarely in the dermatopathology literature and whose immunophenotypic profile has not been well characterized. The clinical, histologic, and immunophenotypic features of 2 cases seen by the authors were assessed, and relevant publications in the literature were reviewed. Both patients with OCOTs were adult women with gradually enlarging, asymptomatic lesions involving the caruncle; they were locally excised. Histologically, the tumors were well-circumscribed nodules comprised of large oxyphilic cells arranged in confluent sheets and forming glandular spaces with secretory material. Microcystic areas and sparse intermingled goblet-cells were also apparent. Nuclear atypia and infiltrative growth were absent. Mitotic activity was absent in one case; a single mitotic figure was identified in the other. Immunostains demonstrated uniform expression of pankeratin and mitochondrial antigens. Both neoplasms were also labeled for markers associated with cutaneous adnexal, lacrimal, and minor salivary glandular tissue, including alpha-1-antitrypsin, gross cystic disease fluid protein-15, carcinoembryonic antigen, lysozyme and MUC1; each case expressed 4 of the 5 substances. Some cells expressed cytokeratins 5/6 and p63 consistent with the presence of basal-type differentiation in a subset of cells. No definite evidence of myoepithelial differentiation was demonstrated, as stains for smooth muscle actin, muscle-specific actin, and S100 protein were negative. Estrogen and progesterone receptor proteins were absent; strong cytoplasmic immunoreactivity for androgen receptor protein was evident, but nuclear staining was absent. The authors conclude that OCOTs show glandular differentiation. A review of the literature disclosed that none of these lesions arising in the caruncle behaved aggressively, in contrast to occasional tumors in other oculocutaneous sites.