Introduction: We report a novel technique for treating solar lentigines that was designed to address the shortcomings of the enlighten^® picosecond laser.
 Methods: A laser with a 532-nm wavelength, 750-ps pulse width, and 2-3-mm spot size was densely applied until distinct immediate whitening was observed throughout the lesion.
 Results: We found that uneven beam profiles resulted in residual pigmentation of larger lesions, whereas high-intensity laser application over a small area enabled complete lesion clearance. Our findings suggest that a small spot size reduces thermal damage to the surrounding tissue, decreasing the risk of post-inflammatory hyperpigmentation.
 Result: A 27-year-old man presented with solar lentigo on his left cheek that had been incompletely removed by multiple treatments with picosecond lasers. The lesion was treated with the enlighten^® laser using a 2-mm spot size, 1.0 J/cm² fluence, and 5-Hz frequency. One month later, no post-inflammatory erythema, hyperpigmentation, or obvious residual lesions were observed.
 Discussion: Our findings suggest that this technique compensates for the enlighten^® device's shortcomings. Moreover, as operation of the present device is straightforward, its use may be feasible regardless of operator experience.
 Conclusion: By optimizing the application method, this technique may improve treatment outcomes of solar lentigines.

 A congenital external lacrimal sac fistula opens from the lacrimal sac or duct into the skin near the inner corner of the lower eyelid. It is considered a relatively rare condition. We encountered a case where the fistula recurred following a resection-only fistulectomy. The fistula was subsequently removed by ligating the stump in our department. The patient has remained recurrence-free.
 Complete removal of the fistula duct is generally required to treat this condition; however, the necessity of ligating the stump remains to be elucidated. In this study, we compared the recurrence rates of this condition using studies reported in Japan and overseas. We found no significant difference in recurrence rates between ligation and resection alone.

 Alveolar soft part sarcoma (ASPS) is a rare malignant soft tissue tumor that predominantly affects young adult women. ASPS constitutes less than 1% of all malignant soft tissue tumors. ASPS typically presents as a gradually enlarging mass in the extremities, head, and neck. However, it can also occur in other parts of the body. Herein, we report a case of ASPS occurring in the pectoralis major muscle of a 69-year-old man. He was referred to our institute with a soft tissue mass in the left thoracic region. CT, MRI, and fine-needle biopsy raised the suspicion of a soft tissue malignancy in the pectoralis major muscle. FDG-PET/CT confirmed the absence of additional lesions beyond the left thoracic region. The patient underwent radical resection of the tumor. Histopathological examination of the resected tumor confirmed the diagnosis of ASPS. Follow-up one year after surgery revealed no signs of local recurrence or distant metastasis. This case is particularly noteworthy as ASPS in the pectoralis major muscle is a rare occurrence. A literature search identified the present case as only the second reported case, and the first in Japan.

 Bilateral orbital floor blowout fractures are rare. Most cases are classified as impure-type fractures, which are characterized by a fracture that extends to the surrounding orbital margin. Bilateral orbital floor blowout fractures of the pure type are extremely rare. Most reported cases of pure-type fractures are associated with assault. In this report, we present two cases of bilateral orbital floor blowout fractures resulting from a single traumatic event. Both cases involved fractures in the bilateral infraorbital walls and nasal bones, without any fractures in the periorbital area; thus, they were classified as pure-type fractures. Notably, we found no evidence of damage to the face guard of the helmet, glasses, or eyes, which suggests that the mechanism of the fracture was due to a buckling force rather than a hydraulic force.

 Lacrimal sac diverticulum is a relatively rare condition characterized by the formation of a continuous cystic structure originating from the lacrimal sac. While it is often asymptomatic, symptoms, such as epiphora, swelling near the medial canthus, and drainage of pus, may occur. Diagnosis is often challenging because there is no specific test. Treatment generally involves the use of antibiotics. Lacrimal sac diverticulum should be considered a differential diagnosis when evaluating a mass in the medial canthus. Herein, we present a case of lacrimal sac diverticulum with repeated episodes of swelling in the medial canthus as the primary complaint.