Combined tumour of aberrant cytokeratin expressing acral lentiginous melanoma and poroma: Diagnostic challenge

Combined tumours are uncommon and therefore these tumours may pose a diagnostic challenge. In the current case report, it is aimed to present the clinicopathological features of a combined tumour including melanoma with aberrant cytokeratin expression and poroma.

Anterior segment optical coherence tomography in ocular surface tumours and simulating lesions

This study aims to systematically review the reported literature on the use of anterior segment optical coherence tomography (AS-OCT) in ocular surface tumours and simulating lesions. A systematic literature search was done using PubMed, Scopus, and Web of Science databases between January 2002 and December 2021. On AS-OCT, ocular surface squamous neoplasia typically demonstrate epithelial thickening, epithelial hyperreflectivity, and an abrupt transition between normal and abnormal epithelium. Conjunctival nevi usually show mildly hyperreflective epithelium of normal thickness, internal hyperreflectivity, and intralesional cysts which is the hallmark of this tumour. Primary acquired melanosis presents with normal thickness epithelium, basal epithelial hyperreflectivity, and absence of cysts. Conjunctival melanoma demonstrates hyperreflective normal/thickened epithelium, hyperreflective basal epithelium, internal hyperreflectivity, and absence of intralesional cysts. Conjunctival lymphoma shows homogenous, low-medium reflective subepithelial lesions with smooth borders, and dot-like infiltrates. Benign reactive lymphoid hyperplasia findings are similar to lymphoma but the infiltrates are more hyperreflective compared to lymphoma. Pterygium shows thickened conjunctival epithelium, epithelial hyperreflectivity, and subepithelial wedge-shaped hyperreflective tissue separated from the overlying epithelium by a cleavage plane. Pinguecula demonstrates mildly thickened epithelium and similar findings with pterygium but does not extend beyond the corneal limbus. This review shows that AS-OCT, as a noninvasive tool, has potential uses in the differential diagnosis of ocular surface tumours and simulating lesions. Major limitations of AS-OCT include limited visualization of the posterior border of thick, keratinized, and pigmented tumours and lack of assessment of large conjunctival tumours in a single cut.

Integrated diagnosis of nevi with severely atypical features and impact of second opinions

BACKGROUND

A subset of melanocytic proliferations is difficult to classify by dermatopathology alone and their management is challenging.

OBJECTIVE

To explore the value of correlation with dermatoscopy and to evaluate the utility of second opinions by additional pathologists.

METHODS

For this single center retrospective study we collected 122 lesions that were diagnosed as atypical melanocytic proliferations, we reviewed dermatoscopy and asked two experienced pathologists to reassess the slides independently.

RESULTS

For the binary decision of nevus versus melanoma the diagnostic consensus among external pathologists was only moderate (kappa 0.43; 95% CI 0.25-0.61). If ground truth were defined such that both pathologists had to agree on the diagnosis of melanoma, 13.1% of cases would have been diagnosed as melanoma. If one pathologist were sufficient to call it melanoma 29.5% of cases would have been diagnosed as melanoma. In either case, the presence of dermatoscopic white lines was associated with the diagnosis of melanoma. In lesions with peripheral dots and clods, melanoma was not jointly diagnosed by the two pathologists if the patient was younger than 45 years.

CONCLUSIONS

A considerable number of atypical melanocytic proliferations may be diagnosed as melanoma if revised by other pathologists. The presence of white lines on dermatoscopy increases the likelihood of revision towards melanoma. Peripheral clods indicate growth but are not a melanoma clue if patients are younger than 45 years.

Dermatoscopic features of Spitz naevi on acral volar skin: Report of 11 cases

Spitzoid melanocytic lesions characterized by spindle and/or epithelioid tumour cells can occur anywhere on the skin but the acral presentation of Spitz naevus is very rare and comprises about <4% of all Spitz naevi. However, data regarding their dermatoscopic features on the acral volar skin are scarce. Herein, 11 cases of acral Spitz naevus involving the glabrous skin with predominant dermatoscopic findings of atypical fibrillar pattern in non-pressure bearing areas, a structureless pigmentation involving both the furrows and the ridges are presented.

Morphology of the trigeminal ganglion: anatomical structures related to trigeminal radiofrequency rhizotomy

BACKGROUND

Trigeminal neuralgia is the most common example of craniofacial neuralgia. Its etiology is unknown and is characterized by severe episodes of paroxysmal pain. The trigeminal ganglion and its adjacent anatomical structures have a complex anatomy. The foramen ovale is of great importance during surgical procedures such as percutaneous trigeminal rhizotomy for trigeminal neuralgia.

OBJECTIVE

We aimed to identify the anatomical structures associated with the trigeminal ganglion and radiofrequency rhizotomy on cadavers and investigate their relationship with the electrodes used during rhizotomy to determine the contribution of the electrode diameter and length to the effectiveness of the lesion formation on the ganglion.

METHODS

Five fresh-frozen cadaver heads injected with red silicone/latex were used. A percutaneous puncture was made by inserting of a cannula through the foramen ovale to create a pathway for electrodes. The relationships between the electrodes, Meckel's cave, trigeminal ganglion, and neurovascular structures were observed and morphometric measurements were obtained using a digital caliper.

RESULTS

Trigeminal ganglion, therefore the electrode in its final position, shows proximity with important anatomical structures. The electrode was inserted posteriorly into the foramen ovale in all of the specimens and was located on the retrogasserian fibers. This study revealed that the electrodes targeting the ganglion and passing through the foramen ovale may cause a radiofrequency lesion due to the contact effect of the dura itself pressing on the electrode. Pushing the cannula beyond the petroclival angle may result in puncturing of the dura propria and moving further away from the target area.

CONCLUSION

The success of radiofrequency rhizotomy is directly related to the area affected by the lesion. Understanding the mechanism of action underlying this procedure will ensure the effectiveness, success, and sustainability of the treatment.

Lesional activation of Tc 17 cells in Behçet's disease and psoriasis supports HLA-class I-mediated autoimmune responses

BACKGROUND

Behçet's disease (BD) presents with lymphocytic and neutrophilic vasculitis of unknown aetiology. HLA-B*51 ERAP1 and IL12R/IL23R are genetic risk factors. IL-23 regulates IL-17A, which controls recruitment and activation of neutrophils.

OBJECTIVES

To determine pathological changes in BD skin lesions related to the complex genetic predisposition METHODS: We characterised the expression of IL-17A and IL-23A in various cell types by immunohistological double staining of sections from papulopustular skin lesions (PPL) of acute attacks of BD and lesions of psoriasis vulgaris (PV), another HLA-class I-associated T-cell mediated autoimmune disease in which excessive T-cell derived IL-17A production promotes neutrophil activation.

RESULTS

We found that in BD lesions, as in psoriasis, actively expanding CD8⁺ T cells were the predominant source of IL-17A. IL-17A⁺ CD8⁺ T (Tc17) cells outnumbered infiltrating IL-17A⁺ CD4⁺ T cells. Unlike the epidermal localisation of CD8⁺ T cells in psoriasis, Tc17 cells in BD lesions infiltrated mainly the perivascular tissue and also the blood vessel walls of dermis and subcutaneous tissue. They colocalised with a marked IL-23A expression by CD11c⁺ dendritic cells (DCs) and CD68⁺ macrophages. IL-17A expression was associated with extensive recruitment of neutrophils around blood vessels that formed neutrophil extracellular traps (NETs).

CONCLUSIONS

In BD, the genetic predisposition may mediate antigen-specific activation and differentiation of a T_c 17 response, possibly targeting endothelial antigens. Neutrophils recruited by IL-17A in this process may enhance tissue damage by extensive NET formation (NETosis). Thus, the IL-23/IL-17 axis presumably controls neutrophilic inflammation in BD vasculitis in the context of a predominant antigen-specific CD8⁺ T-cell response.

Folliculotropic mycosis fungoides: Clinical characteristics, treatments, and long-term outcomes of 53 patients in a tertiary hospital

Folliculotropic mycosis fungoides (FMF) is characterized by a broad clinical spectrum and worse prognosis compared to classical MF. This study aimed to evaluate the clinical characteristics, treatment modalities and long-term outcome and risk factors for progression and survival of FMF patients. We conducted a single-center retrospective study and reviewed 53 patients diagnosed with FMF between 1990 to 2019 in a referral center at Ankara University, Turkey. Regarding to stage at diagnosis, 24 patients (45.3%) had advanced-stage disease (≥IIB). Follicular papules was observed in 66% and alopecia in 49.1% of the cases. Forty-three patients (81.1%) suffered from pruritus. The majority of the patients (92.4%) had at least one systemic therapy. Complete remission was achieved in 24.5% of the patients. The median time of overall survival (OS) was 50 months (range 9-324 months) and 5-year and 10-year OS was 83% and 69%, respectively. Twenty-eight (52.3%) patients progressed to more advanced stages and seven (13.2%) patients died due to MF during the follow-up period. FMF is associated with a progressive course and in most patients, skin-directed therapies were found to be inefficient to control the disease and multiple systemic therapeutic agents were required to control the disease.

Subungual Glomangiomyoma

Glomus tumors are relatively rare benign tumors originated from normal glomus bodies. These tumors make up approximately 2% of all hand tumors and are most commonly found in the nail matrix and proximal nail bed of the hands. Histopathologically, they are classified into solid glomus tumor, glomangioma, and the least common type glomangiomyoma. Here we report an unusual case of subungual glomangiomyoma of the toe with dermatoscopic and histopathologic findings.

Basosquamous carcinoma and melanoma collision tumor in a child with xeroderma pigmentosum

Xeroderma pigmentosum (XP) is a rare autosomal recessive genodermatosis associated with hypersensitivity to ultraviolet radiation (UVR), being due to defects involving the nucleotide excision repair pathway. Patients with XP are prone to develop multiple cutaneous neoplasms including non-melanoma skin cancers and melanoma. Collision tumors in patients with XP have been reported in the literature including the following lesions, actinic keratosis, basal cell carcinoma, squamous cell carcinoma, and in situ melanoma. Herein, we present a rare collision tumor composed of melanoma and basosquamous carcinoma in a 13-year-old XP patient and describe the dermoscopic features.

Lichen sclerosus associated with Nd:YAG laser therapy

Laser is the most efficient and popular method in hair removal. The most common side effects of laser assisted hair removal are pain, erythema, edema, hypopigmentation, hyperpigmentation, blistering, crusting, erosions, purpura, folliculitis, and scar formation ( 1 ). Herein, for the first time we describe a case of lichen sclerosus (LS) following hair removal with long pulsed 1064 nm Nd:YAG laser therapy.

Sellar Embryonal Tumor: A Case Report and Review of the Literature

Primitive neuroectodermal tumors (PNETs) are aggressive, poorly differentiated tumors in children and young adults. However, the embryonal tumor group did not include the central nervous system (CNS) PNET title and ependymoblastoma subtitle in the 2016 World Health Organization CNS tumor classification. Here, we report the case of a 6-year-old boy with a sellar embryonal tumor and present a review of the related literature. To the best of our knowledge, this is the first case of an endoscopically operated sellar embryonal tumor in the pediatric age group.

Nail apparatus melanoma initially diagnosed as nail matrix blue nevus: a case report with dermatoscopy and dermatopathology

We present a case of nail apparatus melanoma in a 50-year-old woman presenting as new and changing longitudinal melanonychia of the right thumb. Very heavy melanin pigmentation involving both the epidermis and dermis interfered with dermatopathological assessment, which initially leads to a diagnosis of nail matrix blue nevus. After consultation with a specialist multidisciplinary clinic the diagnosis was revised to invasive melanoma, a diagnosis consistent with the clinical and dermatoscopic assessment.

A case of acanthosis nigricans as a paraneoplastic syndrome with squamous cell lung cancer

A 55-year-old man presented with oral mucosal ulcers, blackening of both hands, and hyperpigmentation on axillary, anal, and inguinal regions for the last 3 months, which were all progressive. The patient was referred to the oncology department with the diagnosis of acanthosis nigricans for investigation of an underlying malignancy. He was a smoker. A computed tomography scan of thorax revealed enlarged mediastinal lymphadenopathies and a lesion on the left upper lobe. Fine-needle aspiration biopsy of the mediastinal lesion was consistent with squamous cell carcinoma, and biopsies of the skin and oral mucosal lesion also further confirmed the diagnosis of acanthosis nigricans. After docetaxel and cisplatin chemotherapy, a significant improvement in his skin and mucosal lesions was observed with almost complete resolution of the pulmonary lesion and the mediastinal lymph nodes.

Development of poorly differentiated invasive squamous cell carcinoma in giant Bowen's disease: a case report with dermatoscopy

Bowen’s disease (BD) is an in situ form of squamous cell carcinoma (SCC), often occurring in the chronically UV-damaged skin of elderly people. The risk of progression of BD to invasive SCC varies between 3% and 5%, and one-third of invasive tumors may metastasize. Herein we discuss the dermatoscopic findings of a case of giant Bowen’s disease, which progressed to poorly differentiated invasive SCC.

Dermatoscopic findings of atrophic dermatofibrosarcoma protuberans

Dermatofibrosarcoma protuberans (DFSP) is an uncommon locally aggressive mesenchymal tumor with a high local recurrence rate. Atrophic DFSP is a rare variant of DFSP characterized by a non-protuberant lesion. We report on a 23-year-old female, who presented with an atrophic, asymptomatic macule on the right side of her back 2 cm in diameter. Dermatoscopic examination revealed homogenous pigment network on a purplish erythematous background. The histopathological finding of the incisional biopsy material was consistent with DFSP. To our knowledge, this is the second case of atrophic DFSP discussing the dermatoscopic features of this relatively rare condition.

Primary pineal glioblastoma: a case report

Glioblastoma is very rare in the pineal region. We report a case of glioblastoma in this region. This is the 18th case of primary glioblastoma in the pineal region and the second case that survived over two years according the literature. A 60-year-old man admitted with headache and ataxia that continued for the last 3 months. Physical examination was normal. Neurological examination revealed ataxia. There was no motor or sensory deficit. Computer tomography showed triventricular hydrocephalus and isodense rounded mass in the pineal region. Magnetic resonance images revealed a regular-edged heterogeneous contrast-enhanced tumor in pineal region. A ventriculoperitoneal shunt was inserted for hydrocephalus. After surgery, the ataxia and hydrocephalus were improved. Ten days later, serial stereotactic biopsies were performed. Histopathological specimens revealed glioblastoma. The patient was recommended to undergo radiotherapy and chemotherapy. The patient is still surviving without deficit two years after biopsy and shunt operation.

Solid tumors in Turkish children: a multicenter study

BACKGROUND

This paper presents a detailed incidence study on childhood solid tumors comprising a histopathology-based documentation of benign and malignant lesions.

METHODS

The Ankara Pediatric Pathology Working Group collected databases of pediatric solid tumors from six pediatric reference centers in order to analyze the incidence, distribution and some epidemiologic characteristics of the tumors and to establish a multicenter database for further studies. A five-year retrospective archive search was carried out. Excluding epithelial tumors of the skin, leukemia, lymphoreticular system neoplasias, metastatic tumors, and hamartomas, 1362 solid tumors in 1358 patients were classified according to age, sex, localization, histopathology and clinical behavior.

RESULTS

The male/female ratio was 0.9; 14.8% (201) of the patients belonged to 0-1 year age group, 20.7% (281) to 2-4 years, 25.9% (352) to 5-10 years, 22.2% (301) to 11-14 years, and 16.4% (223) to 15-18 years. Among all tumors, 708 (52.0%) were malignant, 645 (47.4%) benign tumors, 2 (0.1%) borderline tumors, and 2 (0.1%) unknown behavioral tumors. Malignant tumors were found in 50.2% (357) of female patients and in 54.0% (349) of male patients. A balanced distribution between benign and malignant entities among children under 18 years was observed. Comparison between the age groups revealed malignant cases outnumbered benign cases under 4 years of age while benign tumor numbers increased after 10 years of age. The most common entities in the malignant group were of sympathetic nervous system origin, while soft tissue tumors far outnumbered the others in the benign group.

CONCLUSIONS

We conclude that the cancer patterns of children in the Ankara region mostly resemble with those of the western population. This study provides useful information on the diagnosis of solid tumors in children and highlights variations in cancer incidence in different age groups.

Epidermolysis bullosa simplex associated with muscular dystrophy and cardiac involvement

We report a new clinical variant of epidermolysis bullosa simplex with muscular dystrophy (EBS-MD) that was associated with cardiac involvement. A 33-year-old patient had atrial fibrillation, pericardial effusion, and hypokinetic left ventricular cardiac walls. The muscle biopsy material revealed diffuse endomysial fibrosis and small atrophic muscle fibers with rounded contours. A positive desmin expression with abnormal localization in the subsarcolemmal groups was observed. We concluded that patients with EBS-MD should be investigated carefully when there are associated cardiac findings.

Primary intracerebral malignant fibrous histiocytoma mimicking a meningioma

We describe herein a patient with primary intracerebral malignant fibrous histiocytoma (MFH) to demonstrate this very rare central nervous system tumor. A 42-year-old male was admitted to our institute with the complaints of headache and speech impairment. Magnetic resonance imaging (MRI) revealed a tumor consistent with meningioma and we decided the surgery. The tumor was excised totally during the initial surgery. Histopathological examination revealed a mesenchymal tumor with an invasion of the adjacent brain and underlying dura mater. On the postoperative 4th month, the follow up MRI showed tumor recurrence at the same location and of similar size. Reoperation was performed and the tumor was again removed gross totally. However, the patient demonstrated a rapidly progressive course leading to death within the first year after the surgery. Two significant points of this case of primary central nervous system MFH are the rarity of its occurrence and its mimicking a meningioma.

Black hairy tongue after allogeneic stem cell transplantation: an unrecognized cutaneous presentation of graft-versus-host disease

Black hairy tongue (BHT) is an unusual condition in adults characterized by marked accumulation of keratin on the dorsum of the tongue, resulting in a hair-like appearance. Herein, we have described 15 patients developing BHT after allogeneic stem cell transplantation (allo-SCT). BHT was generally accompanied by other cutaneous manifestations of cutaneous graft-versus-host disease (GVHD) or a precursor of GVHD. Our experience in this series emphasized that histopathologic evaluation is required for seemingly harmless eruptions like BHT in the posttransplantation period. Given the important prognostic implications of GVHD, physicians should be careful when confronted with BHT.

Dermatoscopy of flat pigmented facial lesions: diagnostic challenge between pigmented actinic keratosis and lentigo maligna

BACKGROUND

The similarity between clinical pictures of pigmented actinic keratosis (PAK) and lentigo maligna (LM) is well known.

OBJECTIVES

To investigate the frequency of dermatoscopic findings suggestive of LM/lentigo maligna melanoma (LMM) in the other facial pigmented skin lesions (FPSL) and to assess the distinguishing dermoscopic criteria of PAK and LM.

METHODS

Eighty-nine FPSL were evaluated with conventional dermatoscopy. The lesions showing one or more dermatoscopic features considered as specific patterns for the diagnosis of LM/LMM, mainly slate-grey to black dots and globules, slate-grey areas, annular-granular pattern, asymmetrical pigmented follicular openings, black blotches, rhomboidal structures, hyperpigmented rim of follicular openings, slate-grey streaks and dark streaks, were included in the study selectively.

RESULTS

PAK was diagnosed in 67, LM or LMM in 20 and lichen planus-like keratosis in two lesions, histopathologically. Eleven essential dermatoscopic features were observed in facial PAK: slate-grey dots (70%); annular-granular pattern (39%); rhomboidal structures (36%); pseudonetwork (36%); black globules (34%); slate-grey globules (33%); black dots (30%); asymmetrical pigmented follicular openings (25%); hyperpigmented rim of follicular openings (21%); slate-grey areas (18%); and streaks (3%).

CONCLUSIONS

PAK has a striking similarity to LM/LMM in clinical and dermatoscopic features, thus representing a diagnostic challange. All dermatoscopic findings except black blotches were observed in PAK. As dermatoscopic diagnosis of a pigmented skin lesion cannot be based on the presence of a single criterion, we may conclude that histopathology still remains the gold standard for correct diagnosis.

The coexistence of thymic carcinoma and multiple granulomas in a Turkish child

Thymic carcinoma, which is a thymic epithelial neoplasm with obvious cytologic atypia, is a rare neoplasm. The authors report on a 10-year-old boy who presented with respiratory distress due to bulky anterior mediastinal mass. Histological and immunohistochemical studies confirmed a lymphoepithelioma-like pattern thymic carcinoma. In addition, evaluation of the specimen showed foci of caseation and multiple granulomas with extensive central necrosis within the thymic tissue. The child received chemotherapy, followed by surgery and radiotherapy. To rule out difficulties of tuberculosis he also received antituberculosis therapy. Two years after cessation of treatment, he is still in remission for thymic carcinoma.

Behçet's disease-like presentation of bullous pyoderma gangrenosum associated with Crohn's disease

A 47-year-old woman presented with a 2-month history of generalized arthralgia and a 10-day history of oral aphthous ulcers. After hospitalization, papulopustular lesions and perianal ulcerations developed. Pathergy test was positive and ophthalmological examination was normal. The presence of oral aphthous ulcers, genital ulcerations, papulopustular lesions and arthralgia, and the positive pathergy test suggested the diagnosis of Behçet's disease (BD). In a few days, positive pathergy reactions and papulopustular lesions evolved into bullous lesions, which were diagnosed dermatopathologically as pyoderma gangrenosum. Two days after the presentation of papulopustular lesions, the patient experienced diarrhoea accompanied by bloody stools and mucus. Histopathological examination of biopsy specimens showed no vasculitis but revealed findings suggestive of Crohn's disease. The patient responded well to treatment with systemic steroids and 5-aminosalicylic acid. Our case demonstrates that the differential diagnosis of BD and inflammatory bowel disease may be perplexing and that these two diseases may be closely related.

Intramedullary mature cystic teratoma of the conus medullaris. A case report

Intramedullary teratoma is extremely rare and to our knowledge has been reported in only nine cases in the literature. We report a case of mature cystic teratoma of the conus medullaris. The case was diagnosed by magnetic resonance imaging and operated with microneurosurgical techniques.

Granuloma annulare on herpes zoster scars in a Hodgkin's disease patient following autologous peripheral stem cell transplantation

Various cutaneous lesions including granulomatous reactions may occur at sites of resolved herpes zoster infection. A 46-year-old man with Hodgkin's disease developed localized granuloma annulare lesions on herpes zoster scars 3 months after allogeneic peripheral stem cell transplantation. This is the first case of granuloma annulare localized on herpes zoster scars that developed following peripheral stem cell transplantation.

An analysis of stereotactic biopsy of brain tumors and nonneoplastic lesions: a prospective clinicopathologic study

BACKGROUND

Appropriate management of progressive, unverified brain lesions should be guided by conclusive pathological diagnosis. Stereotactic biopsy (SB) is established as a less invasive surgical procedure that provides diagnosis. In this prospective study, we analyzed the diagnostic difficulties and risk of SB in the various brain mass lesions, the rate of conclusive pathological diagnosis, and the rate of and the reasons for discrepancy between the intraoperative smear results and conclusive paraffin diagnosis.

METHODS

Using computed tomography (CT) and/or magnetic resonance imaging (MRI), 130 cases underwent SB procedure to assess intra-axial brain mass lesions. A CT-MRI fusion and a multiplanar image processing stereotactic program were used in cases who had lesions adjacent to the neurovascular and critical areas. The intraoperative evaluations were made with the smear preparations (SPs) of 1 or 2 biopsy specimens. The conclusive diagnosis was achieved by paraffin preparations of the remainder of the biopsies. The discrepancy between the smear results and the conclusive diagnosis was analyzed.

RESULTS

Conclusive histopathologic diagnosis was achieved in 99.23% of the cases. A discrepancy between smear results and conclusive diagnosis was detected in 6.98% of the conclusively diagnosed cases. The major reasons for the discrepancy were necrosis and improper quality of the preparations. There was no mortality, and hemorrhage-related morbidity was observed in 1 case (0.7%).

CONCLUSIONS

Necrosis and the improper quality of the smear preparations (SPs) can cause difficulties in establishing a histopathologic diagnosis in SB. Small tissue samples do not decrease the diagnostic yield with the new stereotactic technologies used by an experienced team consisting of a neurosurgeon, pathologist, and radiologist.

Lamivudine vs lamivudine and interferon combination treatment of HBeAg(-) chronic hepatitis B

To determine whether combination treatment of HBeAg(-) chronic hepatitis B is beneficial we studied 78 patients with HBeAg(-), HBV DNA-positive chronic hepatitis B who were randomized to lamivudine, 100 mg, qd, for 12 months or lamivudine-interferon (9 MU, t.i.w.) in combination. In the combination arm, 2 months of lamivudine treatment preceded 10 months of combination treatment. Biochemical, virologic and histologic responses were assessed at the end of treatment, after six and a median 27 months of drug-free follow-up (short- and long-term follow-up, respectively). Virologic response was defined as undetectable HBV DNA with a hybridization assay and biochemical response as normal alanine aminotransferase (ALT). Change in HBV DNA was also assessed by real-time polymerase chain reaction (PCR). Presence of YMDD mutants at the end of treatment was investigated with a line probe assay. Both treatment regimes led to a median 2 log decline in HBV DNA levels. Virologic end of treatment responses were 90 and 92% with mono- and combination treatment, respectively. Corresponding virologic responses at short- and long-term follow-up were 59 and 54%, and 27 and 25%, respectively. Patients having a baseline HBV DNA value > or =200 pg/mL were more likely to relapse within 6 months off therapy than those patients with a baseline HBV DNA level <200 pg/mL (P = 0.041). YMDD mutants were observed in 53% of patients receiving lamivudine compared with 24% of patients receiving the combination regime (P = 0.017). In conclusion, efficacy of combination treatment is similar to lamivudine monotherapy. However, combination treatment decreases the development of YMDD mutant strains compared with lamivudine monotherapy.